Emmanuel Macron says EU door remains open to Britain as May faces calls to soften Brexit

French president Emmanuel Macron has claimed the door to the EU will remain open to Britain during Brexit negotiations that get underway next week.

Speaking in the gardens of the Élysée Palace in Paris in a joint press conference with Theresa May, the newly elected French leader said the decision to leave the EU could still be reversed if the UK wished to do so.

Responding to questions posed by journalists if he agreed with German finance minister Wolfgang Schaeuble who earlier told Bloomberg that Britain would find "open doors" if it changed its mind, Macron said: "The door of course is still open as long as Brexit negotiations have not been concluded, but a sovereign decision to leave the EU has been taken and I respect that decision."

Macron added as that as the negotiations go on it will be more and more difficult “to go backwards.”

With Britain entering a sixth day of political limbo as May is yet to seal a deal to prop up her minority government and faces calls to soften her stance on Brexit, May said the timetable for Brexit negotiations remained on course with talks due to start next week.

May's team will resume talks with Northern Ireland's Democratic Unionist Party (DUP) on a deal to secure their support in parliament after the 60-year-old leader failed to win an outright majority in last week's snap election - a vote she called expecting to strengthen her position.

"I think there is a unity of purpose among people in the United Kingdom," May said following her meeting with Macron.

"It's a unity of purpose, having voted to leave the EU, that their government gets on with that and makes a success of it."

But pressure was mounting for May to change course on the type of Brexit Britain should pursue.

Before the election May had proposed a clean break from the EU, involving a withdrawal from Europe's single market, but now weakened with a minority government, some in her party are calling for a more business-friendly approach.

The Times newspaper said finance minister Philip Hammond would push May not to leave the customs union - an arrangement which guarantees tariff-free trade within the bloc but prohibits members from striking third-party trade deals.

After meeting May for the first time during the French presidential campaign last February, Macron had said the British prime minister should not expect any favours from the European Union during Brexit talks.

He told reporters outside 10 Downing Street at the time that "an exit is an exit."

On Tuesday, May and Macron also said they had agreed on an action plan on counter-terrorism. Both countries have been hit by deadly Islamist militant attacks in recent months.

Macron said Internet companies would be asked to do more to remove content promoting terrorism, access to encrypted content on online messaging systems would be widened, and co-operation with the United States on online content would be improved.