B2B SaaS Guide: Google Ads Agencies in London

Finding a Google Ads agency in London that actually understands B2B SaaS is a nightmare. The city is flooded with agencies, from slick operations in Shoreditch to big corporate players in the City, and almost all of them will pitch you the same tired, generic strategy. They'll talk about 'brand awareness' and 'driving traffic', show you glossy reports full of clicks and impressions, and charge you a hefty retainer for the privilege. But six months down the line, your MRR hasn't budged, and you're left wondering where all the money went.

The problem is simple: they're generalists. The same team that runs campaigns for a local plumber or a fast-fashion brand will be assigned to your complex, high-consideration SaaS product. They don't understand your sales cycle, they don't know how to calculate a permissable Cost Per Acquisition based on your LTV, and they certainly don't know how to generate Product Qualified Leads (PQLs) that your sales team will actually thank you for. They're playing a different game, and you're the one paying for their education. This guide is here to stop that. It's a no-nonsense framework for cutting through the agency fluff and finding a true growth partner in London who speaks your language and focuses on the only metric that matters: profitable growth.

Why are most London agencies so bad for SaaS?

Let's be brutally honest. The typical agency model is built on volume and efficiency, not deep specialisation. They have a templated process they apply to every client because it's scalable. It usually looks something like this: a quick kickoff call, a bit of basic keyword research, launch a few campaigns using broad match, and then send a monthly report. It's a factory line approach, and for a nuanced business model like B2B SaaS, it's a recipe for disaster.

They don't get that your Ideal Customer Profile (ICP) isn't a simple demographic. For one of our B2B software clients, the target isn't just "HR managers in the UK". It's "Heads of People at UK tech scale-ups with 100-500 employees who are struggling to retain top engineering talent". That level of specificity is lost on a generalist agency. They'll just plug "HR software" into Google's keyword planner and burn through your budget reaching a thousand people who have no intention, or authority, to buy.

This leads to a focus on completely the wrong things. They'll celebrate a low Cost Per Click (CPC), without realising those cheap clicks are from students looking for research papers. They'll boast about a high number of 'leads', but when you look closer, they're just low-intent ebook downloads from people who will never become customers. It's all activity, no impact. We had to rescue a campaign for a medical job matching SaaS where their previous agency was proud of a £100 CPA. The leads were terrible. We took over, rebuilt the targeting from the ground up to focus on actual hiring managers with specific pain points, and brought their CPA for a *qualified* user down to just £7. That's the difference between a generalist and a specialist.

How do I find an agency that actually gets it?

You need to change the questions you're asking. Stop asking about their Google Partner status or how many people are on their team. None of that matters. Your entire vetting process should be laser-focused on one thing: proving they have successfully grown a UK-based B2B SaaS company like yours before. Here are the non-negotiable questions you must ask on that first call.

Question 1: "Can you walk me through a UK B2B SaaS case study, starting from the business problem and ending with the impact on MRR?"

This is the most important question. Don't let them get away with vague statements like "we increased leads by 300%". Dig deeper. Ask what the starting CPA was. Ask what the lead-to-customer conversion rate was. Ask how they attributed a Google Ad click to a new subscription three months later. A real expert will relish this question. They'll be able to talk about the challenges, the failed experiments, and the "aha!" moment that unlocked growth. I remember one campaign for a software client using Google Ads where we acquired over 3,500 users at a cost of just £0.96 each. The key wasn't just the low cost; it was demonstrating how that acquisition cost fit within a profitable LTV model, ensuring every pound spent was a direct investment in their growth. A good case study tells a story about solving a business problem, not just about ad metrics. If they can't produce a single, detailed, relevant case study, the conversation is over.

Question 2: "What's your process for understanding my Ideal Customer Profile and their specific nightmare?"

Their answer to this will reveal if they are a strategist or just a button-pusher. A bad answer is "we'll use Google's in-market audiences". A good answer is "First, we'll interview your sales team and your best customers. We need to understand the exact, career-threatening pain point that makes someone search for a solution like yours at 10 PM on a Tuesday. Is it the fear of a compliance breach? The frustration of a broken workflow costing them their best employees? We build our entire keyword and ad copy strategy around that 'nightmare scenario', not around generic industry terms." This shows they understand that B2B buying decisions are emotional, driven by pain and risk. For a deep dive on this, check out this guide for tech founders in London on using Google Ads.

Question 3: "Based on my business model, how would you determine a target Cost Per Acquisition (CPA)?"

This is a trick question. If they give you a number right away, they're guessing. The only correct answer involves them asking YOU a series of questions: "What's your average revenue per account? What's your gross margin? What's your monthly customer churn rate?" They are working towards calculating your Customer Lifetime Value (LTV). Only then can they recommend a sensible target CPA based on a healthy LTV:CAC ratio (typically 3:1). An agency that doesn't build its strategy on the foundation of your business's unit economics is just gambling with your money. They have no way of knowing if the campaign is actually profitable.

To really get a grip on this, you need to know your numbers inside and out. It's the only way to hold an agency accountable and to know if your ad spend is an investment or an expense.

What are the red flags that should make me run for the hills?

Spotting a bad agency is just as important as identifying a good one. The London market is full of smooth-talking salespeople who are experts at sounding confident but lack any real substance. Here are the warning signs that you're talking to the wrong people.

Red Flag 1: The "Guaranteed Results" Promise.

If you hear the word "guarantee" in a sales pitch, end the call immediately. No professional in paid advertising can guarantee results. There are too many variables: market changes, competitor actions, your own website's conversion rate, ad platform algorithm updates. Anyone promising a specific ROAS or number of leads is either a liar or a fool. A true expert will talk in terms of probabilities, benchmarks, and a methodical process of testing and optimisation. They'll promise a rigorous process, not a magical outcome. This is a clear indicator that you should read a bit more on how to approach vetting Google Ads agencies in London properly.

Red Flag 2: Long, Inflexible Contracts.

An agency trying to lock you into a 12-month contract from day one is signalling a huge lack of confidence in their own ability to deliver. They're securing their revenue, not your results. A good partner will be confident enough to propose a shorter initial term, like three months, to prove their value. After that, it should move to a flexible rolling monthly agreement. They should be working to keep your business every single month, not relying on a legal document to keep you trapped.

Red Flag 3: They Don't Challenge You.

A great agency partner isn't a "yes-man". They should be pushing back and asking you difficult questions. If you say your landing page is fine, they should be asking for conversion rate data and suggesting A/B tests. If you say your target audience is "everyone", they should challenge you to narrow it down. If they just nod along and agree with everything you say, it means they're not thinking critically about your business. They're just taking orders. You're hiring an expert for their expertise and their outside perspective, not for their ability to follow instructions. A lack of probing questions is a massive red flag.

Red Flag 4: Vague, Fluffy Reporting.

Ask to see a sample report. If it's full of vanity metrics like impressions, reach, and clicks, but is light on business-focused metrics like Cost Per Trial, Cost Per Qualified Lead, or influenced pipeline value, then you know where their priorities lie. Reporting should tell a story about how ad spend is translating into business growth. It should be transparent about what's working and, just as importantly, what isn't. An agency that hides behind a wall of confusing charts and big numbers is usually trying to obscure a lack of meaningful results. If you are already running ads and you are struggling with this, you might find our guide on how to fix your B2B PPC ROI helpful.

Your offer is the problem, not just the ads

Here's a hard truth: you could hire the best Google Ads expert in the world, someone who knows the London tech scene inside-out, but if your offer is weak, your campaigns will fail. And the most common point of failure for B2B SaaS companies is the call-to-action. The "Request a Demo" button is one of the most arrogant, high-friction requests you can make of a potential customer.

Think about it. You're asking a busy, high-level professional to commit 30-60 minutes of their time to be sold to, based on a few lines of ad copy and a landing page. It's a huge ask with very little upfront value for them. It immediately frames the interaction as a sales pitch, not a problem-solving session. This is why conversion rates on "Request a Demo" landing pages are often abismal, often below 2%.

The solution is to flip the script. Your offer's only job is to provide a moment of undeniable value. You need to solve a small part of their problem for free to earn the right to solve the whole thing. For SaaS, the gold standard is a free trial (no credit card required) or a freemium plan. Let them get their hands on the product. Let them experience the "aha!" moment for themselves. When the software itself proves its value, the sale becomes a much simpler conversation. I've seen clients go from paying hundreds of pounds for a single demo request to generating software trials for under £10, just by changing the offer. The quality of these Product Qualified Leads is also infinitely higher. If you recall the medical job matching SaaS I talked about, a critical part of our strategy was refining the entire funnel, including the offer, to attract the right kind of user. That focus on quality, not just clicks, was how we took their cost per qualified user from a staggering £100 down to just £7.

If a free trial isn't feasible, you need to get creative. Bottle your expertise into a tool or asset. An accounting SaaS could offer a 'Free Burn Rate Calculator'. A cybersecurity firm could offer an 'Instant Dark Web Scan' for their company domain. The goal is to give, not just to ask. This simple shift in mindset can have a more profound impact on your lead generation than any amount of campaign optimisation.

Your Action Plan: The Vetting Framework

Alright, it's time to put this all into practice. Finding the right agency isn't about luck; it's about having a methodical process. You're not just buying a service; you're making a strategic hire. Here is the framework you should follow.

Step 1: The Shortlist.

Forget generic Google searches for "PPC agency London". Instead, look for specialists. Search for things like "B2B SaaS Google Ads agency" or "paid acquisition for software companies". Look at their websites. Do they talk specifically about SaaS? Are their case studies and blog posts about the challenges of B2B tech, or are they generic? Create a shortlist of 3-5 agencies that look like genuine specialists. Check out our guide for vetting SaaS ad agencies in London to get even more prepared.

Step 2: The Discovery Call.

This is where you deploy the questions from this guide. Go into the call with your list and don't be afraid to take control. This is an interview, and you are the hiring manager. Pay close attention not just to what they say, but how they say it. Are they asking you smart questions back? Do they sound like they've solved these problems a dozen times before? A good call should feel like a strategic consultation, not a sales pitch.

Step 3: The Proposal Review.

A good proposal won't be a copy-paste template. It will reference specific points from your conversation. It will outline a clear, phased approach: starting with research and understanding, moving to testing and validation, and then to scaling. It should clearly define what success looks like, using metrics that matter to you (trials, PQLs, pipeline), not just ad metrics. And it should be transparent about fees and contract terms. If it's full of jargon and vague promises, it's a no.

This is the main advice I have for you:

This is a partnership, not a transaction

Ultimately, finding the right Google Ads agency in London is about finding a partner you can trust to act as an extension of your own growth team. It's not about outsourcing a task; it's about insourcing expertise. This process takes time and effort, but the cost of getting it wrong—months of wasted ad spend, missed opportunities, and immense frustration—is far greater. The right partner will not only drive leads but will also provide strategic insights that can help shape your product, pricing, and overall go-to-market strategy. They'll care as much about your churn rate as you do.

If going through this vetting process feels like a lot of work, or if you'd like an expert second opinion on your current advertising efforts, this is exactly what we specialise in. We work exclusively with B2B tech and SaaS companies to build and scale profitable paid acquisition channels.

We offer a completely free, no-obligation strategy session where we'll do a deep dive into your business, your goals, and your current campaigns. You'll walk away with actionable advice and a clear understanding of your opportunities for growth, whether you choose to work with us or not. Consider it the first step in finding a partner who is genuinely invested in your success.