THERESA May has faced down calls for a second Brexit vote, declaring it a “gross betrayal” of trust.

The PM promised not to give in to activists demanding another referendum — saying millions voted to leave the EU two years ago.

Speaking ahead of MPs returning to Westminster this week, Mrs May said voters “trusted that their vote would count; that after years of feeling ignored by politics, their voices would be heard”.

She said: “To ask the question all over again would be a gross betrayal of our democracy — and a betrayal of that trust.”

Writing in The Sunday Telegraph, Mrs May pledged she will not surrender to Brussels in her negotiations over Brexit.

She said: “I will not be pushed into accepting compromises on the Chequers proposals that are not in our national interest.”

It came as senior Labour figures refused to rule out another membership vote.

Campaign group People’s Vote is focused on changing Labour party policy to back another ballot.

Shadow Brexit Secretary Keir Starmer said a second referendum should be “on the table” if Parliament shuns the PM’s EU exit deal.

Brexit Secretary Dominic Raab has said he is “stubbornly optimistic” about getting a deal with Brussels.

A divorce agreement and statement on a future trade deal are set to be agreed this autumn before MPs vote on departure terms.

Progress has been made on security, defence and legal issues but the “backstop” plan for the Northern Ireland border must be made a “matter of urgency”, says the EU’s chief negotiator Michel Barnier.

Meanwhile, Tory voters reckon Mrs May is the politician best placed to unite the country after the UK leaves the EU next March.

She scored plus 22 per cent in a poll.

Scottish Tory leader Ruth Davidson was second with a score of plus seven.