Related Video: Boris Johnson rules out possibility of resigning

Boris Johnson has admitted he cannot remember the lunch at which he is alleged to have groped a female journalist – despite repeatedly denying the incident took place.

It comes as opposition talks to oust the PM if he tries to force through a no-deal Brexit have been plunged into fresh turmoil amid splits over who should lead a temporary government.

And Conservative MP Geoffrey Clifton-Brown has been sent home from the party's annual conference in Manchester after what a Tory spokesperson described as a "totally unacceptable" clash with security staff.

Late in the evening details emerged of Mr Johnson's planned offer to Brussels. In a speech tomorrow he is to say that the EU must "engage" with his proposals or see the UK walk away without a deal.

The plans, reportedly including the offer of a four-year period inside the EU's regulatory framework for Northern Ireland following the end of the transition period in 2021, represent a "reasonable compromise" on his part, the PM is to say.

Mr Johnson's ultimatum will be delivered despite the passing of the Benn Act, which is designed to prevent a no-deal Brexit.

His opponents accused him of being determined to “force an undemocratic and destructive vision of Brexit on the country”.