It did once exist in Britain’s Conservative/Tory party, and here and there a few odd supporters can still be found amongst modern Conservative journalists/commentators, as I note here. In the past and recent past of the Tory party, both Harold Macmillan and Ian Gilmour seem to have been, broadly speaking, Keynesian Tories.
But the use of Keynesian economics, or certainly full-employment Keynesian policy, has long since departed from Conservative government economic policy, just as it has – with the notable exception of about 2008–2010 – in New Labour.
One of the few survivors of the old Tory party is Sir Peter Tapsell.
Last year he gave an interview to the UK Telegraph in which he described how he had been a Tory Keynesian and also admitted (presumably to the shock of some modern Tories) that his greatest political mistake was supporting Thatcherism: