The Conservatives are set to announce plans to help around 250,000 families with the cost of childcare.

Proposals to be unveiled later on Monday will offer up to £50 a week extra per child on top of existing tax credits.

In a move set to differentiate the Tories from Labour, and boost the parties pro-family credentials, the cash will also be available for informal childcare arrangements, including help from grandparents, friends and neighbours.

The scheme is set to cost £460m a year and would be introduced in 2008.

Party leader Michael Howard said it was designed to help parents "get the right balance between work and the rest of life".

"Ours is a way of introducing flexibility into the childcare system and freeing up some of the rigidities of the present government's approach," he told the Sunday Telegraph.

"I think it will be a real value to 250,000 parents."