The Liberal Democrats set up a separate website to promote Richard Foord, its Tiverton and Honiton candidate, but have not done the same for Jamie Needle, who is standing for them in Wakefield.
A “Help us win in Devon” fundraiser also takes pride of place on the Liberal Democrat website, but there was no sign of an equivalent fundraiser for the Wakefield campaign.
A Tory source said: “Keir Starmer and Ed Davey have entered into this grubby back room agreement without consulting any of their members or MPs. They are to all intents and purposes the same party now favouring open borders, extreme gender politics and having a general disdain for Britain.
“They should at least have the honesty to come clean over this deal but nobody expects them to do the decent thing. They are after all the same people who spent four years trying to subvert democracy.”
Hundreds of Labour and Liberal Democrat candidates ran unopposed by the other party in dozens of Conservative target councils at last month’s local elections.
Leaked Conservative analysis showed Sir Keir’s party stood fewer candidates than in May 2018, although both parties have denied allegations of joining forces.