A member of the London Assembly has asked why the Metropolitan Police is still running Windows XP on thousand of its computers.

Figures published by Greater London Authority Conservatives claim that 27,000 Met Police computers are still running the "dangerously out-of-date" software, which launched in 2001.

Conservative Assembly member Andrew Boff said he did not think it was cost effective to keep paying for security patches to keep the software secure.

Microsoft ended security support for Windows XP in 2014, but the government agreed a deal with the technology giant to keep providing support for the thousands of government computers that were still running the software, at a cost thought to be around £5.5 million.

This initial deal ended in April last year.

"Operating Systems age more like milk than wine, and Windows XP is well past its sell-by date," Mr Boff said.

"The Met should have stopped using Windows XP in 2014 when extended support ended, and to hear that 27,000 computers are still using it is worrying.

"My major concern is the security of Londoners' information on this dangerously out-of-date system, but I would also like to know how much money the Met have wasted on bespoke security updates."

The Met is said to be carrying out a scheme to update thousands more of its computers to Windows 8.1.

"I also question the choice to upgrade to Windows 8.1," Mr Boff said in response.

"This is neither the newest version of Windows nor the most used version of the software.

"Staff are likely to be more familiar with Windows 10, but most importantly it will be supported further into the future."

Windows 10 was released by Microsoft last year, and has since received its first major update, the Anniversary Update, which is the newest version of the software available.

The Met said it planned to upgrade around 6,000 more computers to Windows 8.1 by September, while the rest would be covered by an extended deal with Microsoft that runs until April 2017, at a cost of £1.65 million.

"The MPS (Metropolitan Police Service) is undergoing a complete refresh of its information technology processes, infrastructure, and equipment - including its desktop computers," a Met spokesman said in a statement.

"However, the upgrade programme is not as simple as it would be for many other organisations due to the amount of specialist legacy software upon which parts of the MPS still rely.

"Further plans are being developed to address the remaining XP desktops including reducing the overall number used by the organisation, replacing with laptops, tablets and disposing of equipment that cannot support Windows 8.1 and beyond."