GMP computer operating system could pose a hacking risk

GMP computers still running Windows XP

Greater Manchester Police is vulnerable to computer hackers and viruses as more than one in five of its computers were still running Windows XP as of July.

GMP, England's second biggest police force, told the BBC that 1,518 of its computers ran the ageing operating system, representing 20.3% of all the office computers it used.

Microsoft ended nearly all support for the operating system in 2014. Experts say its use could pose a hacking risk.

Dr Steven Murdoch, a cyber-security expert at University College London, said: "Even if security vulnerabilities are identified in XP, Microsoft won't distribute patches in the same way it does for later releases of Windows.

"So, if the [police's] Windows XP computers are exposed to the public internet, then that would be a serious concern.

"If they are isolated, that would be less of a worry - but the problem is still that if something gets into a secure network, it might then spread. That is what happened in the NHS with the recent Wannacry outbreak."

Greater Manchester Police said it was reducing its reliance on XP "continually".

A spokeswoman said: "The remaining XP machines are still in place due to complex technical requirements from a small number of externally provided highly specialised applications.

"Work is well advanced to mitigate each of these special requirements within this calendar year, typically through the replacement or removal of the software applications in question."