Taoiseach Enda Kenny has indicated the British government could trigger Article 50 by December, months earlier than had been indicated.

British prime minister Theresa May said last month her government will trigger Article 50 and begin formal Brexit negotiations by the end of March next year.

Mr Kenny has now raised the prospect of the process starting at an earlier date.

“We know that prime minister May has said she will trigger Article 50 before the end of March. That does not mean it could not be triggered in December or January or February. So we have no time to waste. This is an evolving process.”

The Taoiseach warned the negotiations could get “quite vicious” and Europe could lose the plot if it becomes obsessed with what Britain might or might not get during the discussions.

“There are those around the European table that take a very poor view of the fact that Britain has decided to leave.

“That argument will be fought very toughly in a really difficult negotiating sense.”

In response to Mr Kenny’s comments a Downing Street spokesman said there had been no change in the British government’s Brexit timeline.

With regard to Ireland, Mr Kenny said there was no merit in "camping in Downing Street" and friends should not "overstay their welcome".

Mr Kenny described Brexit as the biggest challenge Ireland has faced in 50 years. Mr Kenny was speaking as he opened a civic forum examining the consequences of the decision of the British people to leave the European Union.

The Taoiseach described the relationship between Ireland and the UK as very good and said “ we intend to keep it that way”.

“ I am not too sure we will camp in Downing Street. Sometimes when friends call they are very welcome but don’t overstay the welcome.

“ This is a really serious matter. Where do we want to be in five, 10, 15 years? We are part of the European Union now.

“Prime Minister May has said as long as Britain is a member it will continue to pay its way and play its part and make its full contributions.

“Europe has got to decide for itself in these negotiations where it wants to be in the next 15 years. If it becomes obsessed with what the United Kingdom might or might not get Europe itself will lose the plot.”

The Democratic Unionist Party (DUP) and the Ulster Unionist Party have declined to attend the event.

He also said there would be no return to the hard border between the Republic and the North of Ireland.

Mr Kenny said the retention of an open border is essential in any negotiations.

Minsters, Fianna Fáil leader Micheál Martin and Sinn Féin First Minister Martin McGuinness are among the attendees.

Sinn Féin leader Gerry Adams said his party would seek to ensure the vote in Northern Ireland, which voted against Brexit, would be upheld.

He said the six counties should be given special designated status in any negotiations.

Mr Adams also criticised the decision of the DUP not to attend the forum. He said the conversation cannot be ignored by the party.

Mr Martin said people in the Republic and the North of Ireland had been persuaded of the benefits of the European Union.

He said now they are faced with the “fallout of a divisive and damaging result not of their making”.

Mr Martin said: “We could spend a lot of time here talking about the politics of what has happened but this would help no one. And the politicians present need to give the wider interests represented here the space to be heard.

“Today and as this process moves forward we have to take a different approach. “There is an urgent need to quickly move forward. We can’t let the confusion and complacency of others dominate.”

Mr Kenny said: “I have agreed with the Prime Minister that there will be no return to the borders of the past. Therefore the retention of an open border is critical.

“Neither I, nor the Prime Minister, desire to limit the freedom of people on both sides of the Irish sea to trade, live, work and travel freely across these islands.

“Therefore we have agreed that the benefits of the Common Travel Area be preserved.”