A ransomware attack on Advanced Computer Systems, the software provider for the UK’s National Health Service (NHS), severely disrupted blood test operations across multiple London hospitals. The cyberattack led to critical delays in patient diagnostics, contributing to the death of at least one individual. The incident exposed systemic vulnerabilities in third-party vendor security, demonstrating how a single breach in a supplier’s infrastructure can cascade into life-threatening consequences for end-users. The UK’s Information Commissioner’s Office (ICO) later fined Advanced Computer Systems £3 million for inadequate cybersecurity measures, including poor backup protocols and insufficient disaster recovery planning. The attack underscored the lethal risks of ransomware in healthcare, where operational disruptions directly endanger patient lives. Beyond financial penalties, the reputational damage to both the NHS and its vendor eroded public trust in digital health systems, highlighting the urgent need for robust third-party risk management in critical sectors.