London’s Metropolitan Police are forsaking windows 7 for a direct upgrade to Windows 8 as they ditch Windows XP from nearly 40,000 PCs.

However, the transition will not be complete by the deadline for end-of-support from Microsoft. So the police have made an agreement with Microsoft for continuing support of the remaining XP systems.

Microsoft charges $200 per PC for a Windows XP custom support agreement. That fee doubles the following year and then again in the third year. It is not known how much the Met will be paying Microsoft to support Windows XP.

The Metropolitan Police has a total of 40,590 PC clients. Those systems range from Windows NT 4, 2000, Vista, XP, 7 and Mac OS X. However, the majority of their systems run XP, to the tune of 38,551 PCs.

The Met is not alone. NHS England and HM Revenue and Customs, which collects taxes, have between them over 1.086 million PCs and laptops. They too are in discussions with Microsoft for custom support.

Most organizations expect to have completed their transition by the end of 2014.