Some British politicians have said another referendum should be held on whether to leave the EU once the terms of departure and likely future relationship between the UK and the economic bloc are known.
Asked about that in an interview with French TV station C News, Europe 1 radio, and newspaper Les Echos, Mr Moscovici said: “The door is open. If the British want to change their mind, that would be very welcome.”
The UK’s Cabinet Office minister, David Lidington, has urged his party to unite to heal growing rifts over how to leave the EU that could threaten British prime minister’s Theresa May’s fragile grip on power.
After a series of public rifts in recent days, Mr Lidington, who works closely with Ms May, said all sides of the ruling centre-right Conservative party should unite to confront Jeremy Corbyn’s opposition Labour party.
“What I say to all my colleagues is the Conservative family needs to come together in a spirit of mutual respect and look at what the bigger picture is showing,” said Mr Lidington.
Ms May is struggling to juggle competing demands from within her party on the best route out of the bloc which the UK is scheduled to leave in March 2019.
In comments likely to galvanise supporters of a clean break with the EU, US president Donald Trump criticised the way Ms May is negotiating Brexit.
Mr Lidington stepped in after a series of public clashes over Brexit, the latest of which saw the former Northern Ireland secretary Theresa Villiers warn that the UK risked remaining in the EU “in all but name”.
Ms Villiers, a cabinet minister under the previous prime minister, David Cameron, and who campaigned to leave the EU in the 2016 referendum, used an article in the Sunday Telegraph to warn against a deal that could lead to a “a dilution of Brexit”.
Many Brexit backers fear that the referendum result may be betrayed, with the government agreeing to have a two-year transition period with the EU in which little changes.
UK finance minister Philip Hammond enraged members of his party last week for saying the UK’s trade relations with the EU would change only “very modestly” after Brexit.
Ms May has appeared vulnerable after calling an election last June only to lose her parliamentary majority. She has remained in power in part as her party remains too divided to rally around a potential successor.
Jacob Rees-Mogg, who chairs the influential European Research Group of backbench Tory Brexiteers, said the chancellor’s recent comments had caused real trouble for the Government.
He said: “I tend to disagree with the chancellor on many things but on this issue he seems to be disagreeing with Government policy, the Conservative Party manifesto and Mrs May’s speeches. This is real trouble for the government. The history of chancellors being in opposition to prime ministers is not a good one or an encouraging one.”
Mr Corbyn has also faced criticism from his party to clarify what relationship he wants with the EU amid signs of growing support for a second vote on whether to leave the trading bloc.