At a summit of European leaders set to give the go-ahead to the next round of Brussels talks, the Prime Minister insisted her departure drive remained on track despite the Government's Commons defeat earlier this week.

"We're on course to deliver Brexit, we're on course to deliver the vote of the British people," she declared on arriving for the EU Council in the Belgian capital.

She also warned her European counterparts that she will battle with "commitment and perseverance" for a trade deal in the next round of Brexit negotiations in the New Year.

But some EU leaders claimed the Commons defeat was a sign that Brexit could still be reversed.

The summit is expected to formally give the green light today [Friday] to the second phase of talks, focusing on trade and the two-year transition period to a new relationship after the UK's scheduled exit from the EU in March 2019.

Over a dinner for the leaders of the 28 EU member states last night, the Prime Minister promised that Britain would remain a "close friend" to the bloc after leaving.

Mrs admitted that she made "no secret of wanting to get onto the next phase and to approach it with imagination and creativity."

She added: “I believe this is in the best interests of the UK and the EU.

“A particular priority should be agreement on the implementation period so we can bring greater certainty for business in the UK and across the 27.”

Mrs May told the leaders she was keen to start discussing the terms of the trade partnership between Britain and the EU.

And while acknowledging many observers would feel that the last few months had shown how difficult the Brexit negotiations could be, she insisted the , UK and the EU had demonstrated what could be achieved with "commitment and perseverance on both sides".

Mrs May was given a round of applause by EU leaders after giving her speech over the dinner in Brussels, summit sources said.

Earlier, Mrs May confessed to feeling "disappointed" that a mutiny by 11 Tory MPs had resulted in a Commons defeat for the Government on an amendment to her flagship EU Withdrawal Bill at Westminster on Wednesday night.

But she insisted her Brexit plans would not be blown off course by the setback.

"I'm disappointed with the amendment but actually the EU Withdrawal Bill is making good progress through the House of Commons and we're on course to deliver Brexit," she said.

She pointed out that both European Commission President Jean-Claude Juncker and the European Parliament had recommended procedure to the second phase of negotiations.

"I am looking forward to discussing that deep and special partnership for the future," she said.

She also dismissed the defeat as a minor setback in the progress of her Brexit plans.

"Just look at the passage of the EU Withdrawal Bill so far. As I say, it has been making good progress through the House of Commons.

"We've actually had 36 votes on the EU Withdrawal Bill and we've won 35 of those votes with an average majority of 22.

"So the bill is making good progress, we're on course to deliver Brexit, we're on course to deliver the vote of the British people."

She added: "We have won 35 out of 36 votes on the EU Withdrawal Bill; it is making good progress in the House of Commons and that means we are on course to deliver on the sovereign vote of the British people to leave the European Union, and that's what we'll be doing."

Some EU leaders seized on Mrs May's Commons set back a sign that Brexit could be stopped.

Austrian Chancellor Christian Kern, on arriving at the summit, said: "I hope that it can be reversed, because there will be a lot of big issues and challenges that are not easy to solve and a lot of tensions in the domestic area in Great Britain."

Using a German expression, he added: "This cake isn't eaten yet."

And Luxembourg's premier Xavier Bettel said: "It's not good for Theresa May. As soon as she negotiates something she will need to go back to London to get approval from the Parliament and this is not making her life easier.

"It doesn't change anything in the agenda, it just makes life more complicated for the UK Government."

He added: "I think we are making good progress but, if every time we announce something there is a risk that it will unravel in London, it is not very good for making concrete progress."

German Chancellor Angela Merkel, the EU's key power broker, said there were "still a few questions remaining open" about the terms of the UK's withdrawal from the EU while adding that there was "a good chance that the second phase can now begin".

EU Council President Donald Tusk admitted the next phase of the Brexit negotiations could trigger divisions between the 27 nations remaining in the EU after Britain departs.

"I have no doubt that the real test of our unity will be the second phase of the Brexit talks," Mr Tusk said.