Collington will be leaving his role as government chief procurement officer at the end of July to become the chief operating officer at recruitment process outsourcing Alexander Mann.
The role of chief procurement officer was created last year and is seen as one of the top jobs in the Cabinet Office, as government seeks to centralise its expenditure across Whitehall.
Sources close to government say Crothers is expected to take the role. But a Cabinet Office spokeswoman said the department was unable to comment about the appointment adding that an announcement is expected to be made shortly.
Crothers has been increasing his profile within government of late, having recently attended an event with deputy CIO Liam Maxwell to discuss licence savings with Oracle and SAP.
At the event Crothers said the Cabinet Office now expects suppliers to treat the public sector as a single customer, adding that the government would increasingly look to purchase direct from suppliers rather than through system integrators. "Even BPO [business process outsourcing] is [an area] we are looking to disaggregate. You can get electricity cheaper than typical BPO provider [are able to offer]," he said.
Cabinet Office minister Francis Maude said of Collington's departure: "Under John's leadership, government has transformed the way it buys common goods and services, generating substantial savings for the taxpayer with around £1.7 billion saved in 2010/11 alone. Thanks to John's work Government now has a much sharper approach to procurement and a much tighter grip on this spending."