BECTA is one of the main reasons for the UK's dependence on Microsoft in schools. This established mono-culture which has a notorious past when it comes to security, so it comes at no surprise that "UK schools [are] extremely vulnerable to hackers," according to recently-involved security experts:
Many primary and secondary schools in the UK thought to be highly vulnerable to cyber attacks following confidential audit of two schools.
NGS Secure recently audited one selected UK secondary school and primary school to ascertain how secure each was.
At the high school, 338 computers were scanned, unearthing over 9,000 instances of missing critical software patches and multiple instances of outdated or missing anti-virus software. According to the auditors these flaws would allow an attacker or virus to exploit the systems without any prior knowledge of the target.