B2B Ad Agency London: How to Choose the Right Partner & Strategy

Finding the right B2B ad agency in London can feel like a proper mission. It's a crowded market and everyone promises the world. But the truth is, most of what makes an agency good has nothing to do with their sales pitch and everything to do with their actual, provable experience and how they approach your specific problems. It's about finding a partner who gets B2B, not just someone who knows how to run a Facebook ad for a t-shirt company.

Over the years, I've seen businesses spend a fortune with the wrong people. So I'm going to walk you through how to spot the good ones from the not-so-good ones, what questions you should be asking, and what a solid B2B strategy actually looks like. This isn't about flashy presentations; it's about the stuff that actually gets results.

So, where do I even begin my search?

Before you even think about Google searches for "b2b advertising agency london", your first port of call should be their case studies. This is non-negotiable. An agency without detailed, relevant case studies is like a builder without any photos of houses they've built. It's a massive red flag.

But don't just glance at the headlines. You need to look deeper. Are they just showing off big vanity numbers like "10 million views"? That's great for a luxury brand launch, and I remember one campaign for a luxury brand where we achieved 10 million views, but for B2B it's often meaningless. What you need to see is evidence that they understand B2B objectives. Are they talking about Cost Per Lead (CPL), Return On Ad Spend (ROAS) for high-ticket sales, or generating qualified trials for software? These are the metrics that matter in your world.

Look for experience in a similar niche to yours if you can. If you're a SaaS company, have they worked with SaaS before? We've run loads of campaigns for B2B SaaS and it's a completely different ball game to, say, eCommerce. I remember one campaign where we took a medical job matching SaaS from a £100 Cost Per User Acquisition all the way down to just £7. That kind of result doesn't happen by accident, it comes from knowing the specific levers to pull in that niche.

You gotta be realistic with results, of course. Your market might be super competitive, or your offer might need some work. But a good agency's case studies should show a clear thought process. They should articulate the problem, what they did, and the result. We provide detailed insights into the strategies and results we've implemented for clients, giving any prospective client a really good idea what we can do for them and whether they should trust us. If you look at an agency's work and it all feels a bit vague or it's all B2C eCommerce when you sell industrial equipment, they're probably not the right fit for you. It's as simple as that.

How can I tell if their 'expertise' is real?

This is the million-dollar question, isn't it? A slick salesperson can make anyone sound like an expert. The real test comes when you actually talk to them. Most decent agencies will offer some kind of free initial consultation or an account review. This is your chance to really grill them.

We offer a free consultation where we'll actually go through a potential client's ad account and strategy with them. It’s not a sales pitch. It’s an hour of genuine, actionable advice. By the end of that call, they know exactly what we think, what we'd do differently, and they've already gotten value from us, whether they decide to work with us or not. That’s the kind of thing you should be looking for. It's a sign of confidence in their own ability. If an agency is cagey with their advice or just gives you generic platitudes, be wary.

The other big thing is to listen for promises. If an agency guarantees you results, run a mile. Tbh, in paid advertising, you can't promise anything. There are too many variables. You can't predict exactly how a market will react, what competitors will do, or how an algorithm will behave tomorrow. An expert knows this. They'll talk about proven processes, testing methodologies, and realistic projections based on experience. They'll talk about what's worked for other B2B clients, like the campaign where we got a $22 CPL for targeting B2B decision makers on LinkedIn, but they won't promise to replicate it exactly for you. They’ll promise to apply their expertise to try and get you those results. There's a big difference.

And then there's the trust factor. Look at their reviews, see what other clients are saying. But honestly, the consultation is your best tool. If you've seen their case studies, spoken to them, and gotten a load of free, helpful advice that makes sense, you should have a good feeling. We sometimes get people asking for references to call our other clients after all that. For us, that's an instant red flag. It shows a fundamental lack of trust from the outset, and that's never a good foundation for a partnership. If you've done your due diligence and still don't trust them, then they're not the right agency for you.

What should a good B2B strategy even look like?

This is where an agency's B2B credentials really get tested. A good one won't just ask for your credit card and start boosting posts. They'll start with some fundamental questions about your business.

The first thing I'd do is ask about your ideal customer. Who are the companies you sell to? More importantly, who are the specific decision-makers within those companies? Is it the Head of Sales, the CTO, the Operations Director? The entire strategy hinges on this. You can't hit a target you can't see.

Once we know who we're targeting, the next question is: are they actively looking for a solution like yours right now?

-> If they ARE actively searching: This is where Google Search ads are usually your best bet. People are literally typing their problems into Google. For most business services, this is the lowest hanging fruit. You're catching them at the exact moment of need. A good agency will immediately start talking about keyword research, competitor analysis, and building high-intent campaigns around terms like "industrial cleaning services london" or "b2b data enrichment software".

-> If they AREN'T actively searching: This is where things get more complex, and social media ads come into play. But not just any social media. For B2B, this usually means LinkedIn. Why? Because the targeting is designed for it. You can specifically target by job title, company size, industry, and even specific company names. We've used this to get brilliant results, like generating leads for high-ticket industrial products. Trying to do that on Facebook is much harder. You can use their limited B2B targeting like "small business owners", but it's a blunt instrument in comparison.

A good agency will also challenge your ideas about funnels. For B2C or low-ticket offers, a classic funnel works fine. But for high-ticket B2B markering, trying to get a CFO to click 'Buy Now' on a £20,000 service package from a single ad is a fantasy. The goal is different. The goal is to generate a qualified lead, start a conversation, get them on a sales call, and then offer a custom solution that fits their needs. The ads are just the first step in a much longer sales cycle. An agency that doesn't understand this distinction will waste your money.

If they suggest LinkedIn, what should that strategy involve?

Okay, so let's say the agency correctly identifies that your audience isn't actively searching, and LinkedIn is the place to be. A top-tier agency won't just say "let's do some LinkedIn ads". They'll have a very specific, methodical approach.

First, it's all about nailing that targeting. As I said, this is LinkedIn's superpower. They should work with you to build a very clear picture of your Ideal Customer Profile (ICP). This isn't just a vague idea; it's a concrete list of attributes. I've worked on many B2B campaigns where this was the most important step.

Here's a simplified example of what that process looks like, say for a company that sells contact data enrichment software:

Next, they'll talk about objectives and ad formats. What's the goal? Is it to generate leads directly? Or is it to start conversations? The ad format you choose depends on this.

• -> Lead Generation: This is a common B2B goal. The agency will probably suggest testing Sponsored Content ads (the ones that appear in the feed). They might test sending traffic to a dedicated landing page vs. using LinkedIn's own Lead Gen Forms. The Lead Gen Forms often get a lower CPL because they're so easy for the user (their info is auto-filled), but the lead quality can sometimes be lower. It's a trade-off that needs testing. I usually run sponsored content campaigns for lead gen and test both approaches.
• -> Starting Conversations: This is a bit more like paid cold outreach. Conversation Ads (formerly InMail) can work well here. They land directly in the decision maker's inbox.

A good agency will also have a clear plan for creative testing. Should you use a static image ad to get the message across quickly? Or a video ad to pre-qualify leads by having them watch a short demo first? Maybe a carousel ad to showcase different features or service tiers? They should have a point of view on this, based on your offer and their experience. For example, as I mentioned, one of our B2B software clients got 4,622 registrations at just $2.38 each using Meta ads, which shows that sometimes you need to test platforms, but a solid creative and offer strategy is universal. The agency should be talking about a structured testing plan, not just throwing one ad out there and hoping for the best.

And what if Google Ads is the right path?

If your potential customers are actively searching, then a good agency will pivot the conversation to Google Ads. But again, it's the depth of their proposed strategy that separates the experts from the amateurs. They shouldn't just talk about 'doing SEO' or 'running some ads'. It needs to be far more specific and tied to your business goals.

The first thing they should focus on is your website. This is absolutley critical. I've seen so many businesses come to us with failing ad campaigns, and the problem isn't the ads – it's the website. An agency that is willing to take your money without first critiquing your website is not an agency you want to work with. They should be brutally honest. They should tell you if your site is slow, if the copy is weak, or if there's no clear Call To Action (CTA). Your website is the destination. If the destination is a dead end, spending money on ads to send people there is just burning cash.

A good agency will talk about your sales process. What do you actually want a potential lead to do?

• -> Do you want them to fill out a detailed form?
• -> Do you want them to schedule a 15-minute intro call directly in your calendar?
• -> Do you offer a free audit or strategy review as a hook?

Whatever that first step is, your landing page needs to be a machine built for that one single purpose. A professional copywriter can make a huge difference here, crafting a persuasive argument for why that visitor should take action right now. A good agency will either have this skill in-house or have partners they work with. They'll understand that the words on the page are just as important as the targeting of the ad.

Then comes the ad campaign itself. The core of a B2B Google Ads strategy is keyword research. They should be able to brainstorm and show you the kind of terms they'd target. It's not just about broad terms. It's about finding the high-intent keywords that signal someone is ready to buy. For example, instead of just "AI services," they might target more specific, long-tail keywords like:

• -> "AI implementation service for finance"
• -> "b2b software agency london"
• -> "emergency electrical repair for businesses" (if you were a service business)

The key is capturing intent. They should also talk about campaign structure, ad extensions (like phone numbers or links to specific pages), and negative keywords (to stop your ads showing for irrelevant searches). It's a detailed, technical discipline, and their ability to talk about it fluently is a huge indicator of their competence.

What's a realistic budget and what results can I expect in B2B?

This is always a tricky one, because 'it depends' is the honest answer. But a good agency should be able to give you some realistic ballpark figures based on their experience and data. They shouldn't pluck numbers out of thin air.

For B2B, you have to accept that leads will be more expensive than in B2C. You're targeting a much smaller, more valuable audience of decision-makers. As I talked about earlier, one B2B software campaign we ran on LinkedIn where we were happy to achieve a $22 Cost Per Lead, because each of those leads was a highly qualified decision-maker at a target company. Closing just one of them would pay for the campaign many times over. As I mentioned, in another B2B software campaign on Meta, we got registrations for $2.38, but the qualification process was different. The platform and the offer dictate the cost.

Here’s a rough idea of what you might see, based on my experience. These are just estimates to give you a framework.

When it comes to ad spend budget, I usually recommend starting with at least £1k-£2k per month to get enough data to make decisions. But it's simple maths: if you know you need 20 leads a month and your target CPL is £50, then you need £1000 in ad spend. The agency should help you work this out.

Crucially, they should also manage your expectations about ROI. B2B sales cycles can be long. You might generate a lead in January that doesn't become a customer until June. An agency that understands B2B knows this and will focus on leading indicators like the number of qualified leads, meetings booked, and the cost to acquire them, rather than just immediate sales. They should be a partner in your growth, not just a vending machine for clicks.

What are the biggest red flags I should run away from?

We've touched on a few, but it's worth putting them all in one place. If you spot any of these during your search for an agency in London, you should be very, very cautious.

1. Guarantees and Promises. I'll say it again because it's the most important one. No real expert will ever guarantee results. They guarantee a process, they guarantee expertise, they guarantee hard work. They do not guarantee a specific ROAS or CPL.
2. Lack of Relevant Case Studies. If they can't show you they've successfully navigated the B2B landscape for other clients, what makes you think they can do it for you? A portfolio of pretty eCommerce ads is not experience in B2B.
3. Ignoring Your Website. If they're eager to start running ads without a thorough discussion about your landing pages, your offer, and your user experience, they're setting you up to fail. They're just focused on billing you for ad management, not on getting you results.
4. A 'Secret Sauce' or Vague Strategy. An expert should be able to explain their strategy to you in plain English. If it all sounds like mystical jargon or they're cagey about their methods, it's often because they don't have a proper one. The fundamentals of good advertising aren't secret; it's the execution that requires skill.
5. High-Pressure Sales Tactics. A great agency is usually busy. They don't need to bully you into signing a contract. The sales process should feel consultative and helpful, not like you're buying a used car.
6. One-Size-Fits-All Approach. If their pitch sounds like it could be for any business, it's probably not right for yours. B2B requires a tailored strategy. They should be asking lots of questions about your business before they start proposing solutions.

Finding the right partner is a process of elimination. These red flags will help you quickly weed out the agencies that aren't a good fit, so you can focus your time on the ones that show genuine promise and expertise.

This is my main advice for you:

Finding the right B2B advertising agency in London boils down to a clear, methodical process of due diligence. It's not about being wowed by a fancy office or a slick pitch. It's about finding true expertise that aligns with your specific business needs. I've detailed my main recommendations for you in the table below. Follow this checklist, and you'll be in a much stronger position to make the right choice.

This process might seem like a lot of work, but choosing an advertising partner is one of the most significant decisions a business can make. The right one can transform your growth trajectory; the wrong one can set you back months and burn through your budget with little to show for it.

It’s not just about setting up an ad and hoping for the best. It's about deep research into your audience, methodical testing of targeting and creative, continuous optimisation of your landing pages, and a clear understanding of the complex B2B sales journey.

That's where professional help can make a huge difference. With years of experience specifically in the B2B advertising landscape, a specialist consultancy can help you bypass the costly trial-and-error phase. We can provide insights you might not have thought of and take over the entire implementation and optimisation process for you, ensuring that every pound you spend is working as hard as possible to grow your business.

If you’d like to see how this approach could apply to your business, feel free to book a free, no-obligation consultation with us. We’ll be happy to review your current strategy and give you our honest, expert opinion on how you can get better results.

Hope that helps!