The true cost of a cyber-attack vs. the cost of penetration testing  

When budgets tighten, cybersecurity is often one of the first areas to be sidelined and penetration testing is viewed as a 'nice to have' rather than a necessity. But in reality, it's one of the smartest investments a business can make. 

Just a single breach can cause financial, operational, and reputational chaos that far outweighs the cost of regular security assessments. 

From regulatory fines and ransomware payouts to lost customers and long-term brand damage, the hidden costs of a cyberattack quickly add up. And as the threat landscape becomes increasingly aggressive, particularly across SaaS platforms, APIs, and cloud environments, businesses can no longer afford to gamble on reactive security. 

In this post, we'll compare the true cost of cyberattacks with the cost of proactive penetration testing, using real-world UK examples to show why prevention is far more affordable than recovery. 

When faced with a cyber-attack, the costs don't stop at paying a ransom or fixing a few systems. The real impact cuts much deeper and often lingers long after, too. 

Direct costs are the ones that show up immediately. Businesses often face ransom payments, emergency IT recovery bills, legal fees, forensic investigations, and public relations costs to manage the fallout. And depending on the scale of the attack, those bills can quickly run into the millions. 

But indirect costs can be even more damaging over time, as brand reputation takes a hit and customers lose trust and ultimately take their business elsewhere. Regulatory bodies step in with fines and investigations. Operations can grind to a halt for days or even weeks, leading to lost revenue and missed opportunities. 

For UK businesses, the regulatory pressure is only getting heavier. Under GDPR, serious breaches can result in fines of up to 4% (or £17.5m, whichever is higher) of annual global turnover. The Information Commissioner's Office (ICO) has been stepping up enforcement too, particularly around personal data breaches. And for businesses operating in the financial sector, the new DORA (Digital Operational Resilience Act) regulations are adding another layer of cybersecurity compliance, with strict requirements around incident reporting and risk management. 

The bottom line is cyber-attacks aren’t just an IT issue; they’re a business continuity crisis, and an expensive one at that. 

Marks & Spencer (2025) 

In April 2025, retail giant Marks & Spencer was hit by a serious cyber-attack that forced them to halt online orders and disrupted contactless payments across all their stores.

The financial impact was immediate with M&S reporting a £120 million loss in just the first quarter, alongside a 15% drop in share price. It’s a stark reminder that even trusted brands aren’t immune, and that downtime quickly turns into lost revenue. 

British Library (2023) 

The British Library suffered a ransomware attack in late 2023, when the Rhysida group stole 600GB of sensitive data and crippled its online services. Efforts at recovery went on for months, costing between £6 million and £7 million, wiping out a large chunk of the library’s financial reserves. But beyond the money, the attack damaged public confidence in one of the UK’s most respected cultural institutions. 

Synnovis (2024) 

In June 2024, Synnovis, a major NHS pathology provider, was taken offline by a ransomware attack. The company had to fall back on manual blood testing processes, causing huge delays and backlog in patient care. The attack left Synnovis facing a £32.7 million hit - a loss that dwarfed its previous year’s profits and shows just how quickly a cyber-attack can overwhelm even critical public services. 

Southern Water (2024) 

Early 2024 saw Southern Water targeted by the Black Basta ransomware group, with hackers getting access to customer data. The incident cost the company £4.5 million in recovery and remediation expenses, not to mention the lasting damage to customer trust at a time when utilities were facing heavy scrutiny over service quality. 

British Airways (2018) 

British Airways experienced a major breach in 2018 when attackers stole personal data and payment details from over 400,000 of their customers. The ICO handed BA a hefty £20 million fine and while the airline absorbed the penalty, the real damage was to its reputation and customer loyalty during a critical time for the travel sector. 

TalkTalk (2015) 

TalkTalk’s 2015 data breach exposed personal details of 157,000 customers, leading to a £400,000 fine and a total cost of around £77 million after customer losses and response costs were factored in. The incident became a textbook case of how slow responses and poor public communication can turn a security breach into a full-blown reputational crisis. 

It's easy to view pen testing as just another IT expense but compared to the cost of dealing with a cyber-attack, it's a relatively small investment and one that can save many businesses millions in the long run. 

Depending on the scope and complexity, a professional penetration test typically starts from just a few thousand pounds. And even for larger projects involving cloud environments, APIs, and web applications, the costs are modest when weighed against the fallout from a serious breach. 

Penetration testing isn’t just about ticking a compliance box; it's about identifying real vulnerabilities before attackers do, whether that’s a weakness in a customer-facing web app, an unsecured API, a misconfigured cloud platform, or a gap in your internal network security. 

A well-executed test doesn't just uncover technical flaws - it highlights risks to your business operations, customer trust, and even your ability to meet regulatory requirements. In a world where attacks are getting smarter and regulatory pressure is tightening, regular pen testing gives you the clarity and confidence to stay a step ahead. 

For UK businesses especially, with GDPR, ICO enforcement, and growing standards like DORA in finance, taking a proactive approach isn't just good practice, it's becoming essential. 

Every breach today carries consequences that go far beyond technical fixes. Decision-makers, from the CEO, the COO, to the board and beyond are now responsible for managing cyber security risks in the same way they manage financial, legal, or operational risks. 

It’s not just about patching a vulnerability. It’s about protecting the future of the business. When weighing up the value of penetration testing, leaders should be asking: 

• What would a major breach cost us in regulatory fines? 

• How much customer trust would we lose, and how long would it take to rebuild? 

• What would the impact be on our brand reputation five years from now? 

Penetration testing acts as an insurance policy against catastrophic damage providing the insight needed to shore up defences before attackers find the gaps and gives leadership the evidence they need to demonstrate due diligence to regulators, investors, and customers alike. 

For businesses navigating GDPR obligations, ICO scrutiny, or new frameworks like DORA, regular testing and strong data protection practices aren't just technical exercises - they're fundamental to business resilience.