A Brexit deal could be agreed by negotiators in Brussels in secret on Sunday before being presented to the British Government next week, it has been claimed.

Internal documents, believed to be from the team working under chief EU negotiator Michel Barnier, have been leaked in Germany.

Reporters from one of Germany's largest newspapers, Süddeutsche Zeitung, were allegedly given access to documents which carried a timetable.

On the papers, it was claimed an agreement on the Brexit deal with Britain should be reached on Sunday.

The 'provisional timetable' and its content was presented to the EU ambassadors on Friday to make them aware of the EU's position, it was claimed.

Highlighted in red on Sunday, the papers say: 'Deal made, nothing made public (in theory)'.

According to the same timetable, Britain will be given access to the offered deal on Monday.

Within days, if it is agreed, there should be a joint public announcement by British Brexit Minister Dominic Raab and EU Chief Negotiator Michel Barnier in Brussels.

However, the paper reports there was still heated exchanges on the trade agreements after the official leave date and the following, 'transition phase' ends, on Saturday.

Michel Barnier could offer a deal to the UK on Monday after it is agreed by his negotiating team

This week, the Irish border appeared to be the major sticking point for negotiations.

Michel Barnier did not appear to be close to making a deal, or backing down over the EU's demands on the border.

The EU negotiator insisted 'checks' would be needed between the UK and the bloc in future, and they could not happen between Northern Ireland and the Republic.

In a speech in Brussels, Mr Barnier repeated his plan for the province to stay within the EU's customs jurisdiction - suggesting barcode scanning and other technology could be used to ease 'political sensitivities'.

Under the European Commission's 'backstop' plan for the Irish border, customs and VAT checks would be carried out using existing customs transit procedures, to avoid the need for physical inspections at the border, he said.

Mr Barnier vowed he would keep fighting to protect the integrity of the EU single market.

'Brexit brings no added value. It is a negative negotiation. It is a lose, lose game,' he said.

Mr Barnier also said Britain could ease the situation by joining a customs union - something the PM has ruled out as it would make trade deals elsewhere almost impossible.

In a stinging putdown, he took aim at Mrs May's Chequers blueprint for future trade, warning it would undermine the single market and give the UK a 'huge competitive edge'.

Mrs May has insisted the idea is unacceptable as it would risk splitting up the UK.

There have however been faint signs of progress amid reports that the two sides are now working on a single text of a divorce agreement - rather than making counter-proposals.

The intervention came amid a desperate scramble to put together a package that is acceptable to both sides.

An apparent suggested solution would be that Northern Ireland could remain in the European internal market for a limited period of time to prevent a hard border.

However, Northern Irish politicians have repeatedly rejected offers which sees their people treated differently to the rest of the United Kingdom.

Earlier this week Michel Barnier was critical of what the UK offered to Brussels - but a counter offer is in the making, it is believed

Theresa May will have a difficult week ahead to get her DUP colleagues onside if a Brexit deal cannot solve their issues with the Irish border proposals

Mrs May is thought to be trying to unlock the negotiations with new plans for a 'backstop' to avoid a hard Irish border.

It could effectively keep the whole UK in the customs union as a 'temporary' measure until a broader trade agreement is finalised based on her Chequers blueprint.

But there are also likely to be increased regulatory checks in the Irish sea to protect the EU single market.

That could destroy relations between Mrs May and the DUP - which has warned it has a 'blood red' line on the issue.

Any agreement this weekend will be discussed by the General Council and then approved by the 27 Heads of State and Government at their EU summit meeting on Wednesday evening, it was claimed .

For the following day, the notes state: 'Deal with Theresa May confirmed in the European Council'.