Ukip could hand Theresa May a landslide victory in the General Election after deciding not to put up candidates in at least 29 marginal constituencies that are predominantly held by Labour.

Paul Nuttall, the Ukip leader, has decided not to stand candidates in constituencies where a sitting Tory MP supported a hard Brexit or where the Conservatives have the chance to oust Europhile MPs.

The decision means that the Tories could make gains by picking up Ukip voters in a swathe of seats in Labour's traditional heartlands in the Midlands and the North, along with several London marginal constituencies.