Justine Greening, the former education secretary rumoured to be plotting a bid to become London Mayor, should not be allowed to become the Conservatives' candidate if she rebels over the Government's Brexit legislation, Brexiteers have said.

One leading pro-Leave figure claimed there was "no way" an MP who defied Theresa May over the Withdrawal Bill could be put forward to represent the party in the capital's 2020 election.

The comments come as a handful of pro-Remain Conservatives prepare to rebel in a key vote on the legislation when it returns to the Commons on Wednesday.