The UK's withdrawal from the European Union "cannot be delayed or cancelled", French president François Hollande has said, reports the Belfast Telegraph.
Mr Hollande was speaking after talks with David Cameron, during which he assured the prime minister of his continued commitment to allowing UK border guards to carry out checks on ferry and train passengers on French soil after Brexit.
The president said that following last week's historic referendum vote to quit the EU, British voters are "beginning to understand" what they stand to lose. But he indicated that any second thoughts about the outcome have come too late.
Mr Hollande told the AFP news agency: "Being in the European Union has its advantages and I think that is what the British are beginning to understand, what those who are tempted by the Brexit are going to reflect upon.
"But the decision has been taken - it cannot be delayed or cancelled. Now we must take the consequences."
A survey by Opinium Research found 7% of Leave voters now regret their choice, while a BMG poll for the Evening Standard found 13% regret their vote to some degree. The BMG survey suggested that Remain would win a referendum held now by a margin of 45%-40%.
Opponents of UK withdrawal warned during the campaign that Brexit could lead to border controls being shifted to the British side of the English Channel, with the danger of a migrant encampment like the Calais "Jungle" springing up in Dover.
In the wake of last week's result, Xavier Bertrand, the president of the Hauts-de-France region which includes Calais, called on Mr Hollande to revoke the 2003 Le Touquet treaty which allows so-called "juxtaposed controls" on either side of the Channel.