Former Prime Minister Tony Blair has said it is not too late to stop Brexit, as the UK reaches one year to go until it leaves the European Union.
Mr Blair, a Remain campaigner, told BBC Radio 4's Today programme that it was "more likely... than a few months ago" that Brexit could be stopped.
He said the "sensible" option was to "take a final decision" once the terms of the deal have been set out.
It comes as Theresa May pledges to keep the UK "strong and united" post-Brexit.
The prime minister has pledged to make a "success" of Brexit as she makes a whirlwind tour of the UK - visiting England, Scotland, Wales and Northern Ireland, seeking to appeal to those for and against Brexit.
Mr Blair, who was Labour prime minister from 1997 to 2007, said: "I think it's more likely we can stop it now than a few months ago.
"I always say to people the likelihood is it happens, but it doesn't have to happen, and the first place that's going to decide it is Parliament and MPs should vote according to their conscience."
The UK is due to leave the EU on 29 March 2019 with plan being to then enter a 21-month transition period.
At some stage - most likely in October - the prime minister will put an outline of the Brexit deal to Parliament.
Liberal Democrat deputy leader Jo Swinson, who is campaigning for a second referendum once a final Brexit deal is agreed, told BBC Radio 4's Today programme that the public should have a final say because there was a lot of new information available since the June 2016 vote.
"Once those details are becoming clearer, as the government comes towards the end of the negotiations, then it ought to be up to the people to decide what path we, the country, take," she said.
"There is still a real chance that we should be able to choose, if that's what we want, a different path and not go down the Brexit route."
On Wednesday, shadow foreign secretary Emily Thornberry faced criticism from EU campaigners and her own party after she suggested the government's Brexit deal could get Labour's backing in the Parliamentary vote later this year.
But shadow chancellor John McDonnell has defended Ms Thornberry's comments, emphasising her "sarcasm" - calling it a "blah, blah, blah" deal, in response to a journalist's question.
He told BBC Radio 4's Today programme that Labour's six tests - which include maintaining the benefits of the single market and customs union - were "nowhere near being met".
Labour would not vote for the deal unless "the government are sensible and they negotiate properly... [so we can] get a deal that meets the six tests", he said.