The Taoiseach has warned that the Irish border backstop is "not on the table" as efforts to achieve a Brexit breakthrough continue in Brussels.

Leo Varadkar met with UK Prime Minister Theresa May this morning as both leaders arrived in Brussels for the EU Council Summit.

Mrs May intends to use the meeting to try and secure "legal and political assurances" on the backstop from her European counterparts.

It's after she survived a bruising confidence vote in her Tory Party leadership last night - and scrapped a Parliamentary vote on the Brexit Withdrawal Agreement in the face of stiff domestic opposition.

Mr Varadkar said his meeting with Mrs May turned up some ideas that "made sense" while others were "more difficult."

“The backstop is not on the table”. Leo Varadkar very clear heading into negotiations with Theresa May and the EU27 #Brexit pic.twitter.com/xIVtkYDwIz

— Sean Defoe (@SeanDefoe) December 13, 2018

Backstop

He warned however, that there can be no re-negotiation of the backstop.

"I don't think we could agree to anything that would change the content of the treaty; change the content of the Withdrawal Agreement," he said.

"So we will have to work out exactly what those assurances are; what those explanations are and what form they will take.

"What I can say is that the backstop is not on the table. It needs to be there for a number of reasons."

"It needs to be there to give us the assurance that there will be no hard border between Ireland and Northern Ireland no matter what happens - thus protecting the Good Friday Agreement and the peace process.

"It needs to be there for European reasons as well - to give Europe the assurance that the open border will not become the back door to the single market and also to ensure that Ireland will not be used as leverage by either side in talks on the future relationship."

EU leaders arriving for the Council summit in Brussels. They’ll hear the UK’s pitch but the message that the backstop isn’t changing is very clear pic.twitter.com/upSGqENRjN

— Sean Defoe (@SeanDefoe) December 13, 2018

Article 50

He said the EU respects the UKs decision to leave but noted that "it does mean that there is a special obligation on them now to come up with the solutions."

"The threat of no deal is the threat to Britain and its own economy, a threat to Ireland and to Europe," he said.

"That threat can be withdrawn at any time by the UK should they choose to revoke Article 50 or, if that is a step too far, to extend it to allow us more time and to allow Britain more time to decide what it wants.

"That is certainly an option but my preferred option is to ratify the deal that we have."

Assurances

He said the agreement is "far from perfect" but said it is the best option for all involved, adding, "I sincerely hope it can still be ratified in the next couple of weeks."

"When it comes to the assurances that Prime Minister May is seeking; as the EU we are very keen to offer explanations, assurances, clarifications - anything that may assist MPs to understand the agreement and hopefully to support it," he said.

"But the backstop is not on the table."

Britain's Prime Minister Theresa May shakes hands with Taoiseach Leo Varadkar in Brussels, 13-12-2018. Image: Sky News via AP

Negotiations

Earlier Mrs May said she does not expect any "immediate breakthrough" as she continued her meetings with EU leaders.

"What I do hope is that we can start working as quickly as possible on the assurances that are necessary," she said.

She said she understood the concerns of her Government colleagues about "this issue of the backstop and that they do not want it to be permanent."

"What I will be talking to European leaders about here today is what I think we need to get this deal over the line," she said.

"I have already met Leo Varadkar; I am going to be addressing the European Council later."

In a phone call last night, the Taoiseach and the European Commission President Jean-Claude Juncker agreed to work to provide reassurance to the UK - however they reiterated that the Brexit Withdrawal Agreement "cannot be re-opened or contradicted."

No deal

Speaking in the Dáil this afternoon, the Tánaiste Simon Coveney said over 1,000 extra staff could be hired early next year in Irish ports and airports in preparation for a no deal Brexit.

He said the Government will provide an update on its contingency plans for a 'no-deal' scenario next week.