The prospect of a breakthrough in Brexit negotiations before the end of this month looks bleak as the British government and European Union remain as far apart as ever over the issue of a backstop agreement covering the Northern Ireland border.

There had been hopes talks would progress sufficiently for a summit of European leaders to take place this month for the signing of a draft deal which could then be put forward for parliamentary ratification before Christmas.

But that now looks unlikely, piling more pressure on British Prime Minister Theresa May as she goes into the new year, with Britain's scheduled date to leave the EU on March 29, 2019 growing ever closer.

In a speech in London on Monday, May said talks had been "immensely difficult" but were now in the "endgame", while repeating that she was keen to reach an agreement for Britain's departure from the 28-country political and economic group but "this will not be an agreement at any cost".

According to the BBC, the much-discussed backstop plan is the only significant sticking point between Britain and EU negotiators.

The backstop is a temporary safety net solution to avoid a hard border between Northern Ireland, part of the UK, and the Republic of Ireland, an EU member state. Currently there is no hard border and if the two sides cannot agree a customs arrangement in time for the end of the post-Brexit transition period, which is currently scheduled to last until December 2020, a temporary solution is required.

The EU thinks any backstop should see Northern Ireland remain in a customs union and single market until the UK comes up with an alternative. May, however, wants an agreement which would see the whole of the UK stays in the customs union, which the EU has previously said is not acceptable.

On Monday Ireland's Deputy Prime Minister Simon Coveney told reporters in Brussels that there was "still clearly work to do" on the issue.

At home, May faces internal pressure from both sides, both pro and anti-Brexit, over negotiations. So far six members of the cabinet have resigned over her handling of the issue, most recently Transport Minister Jo Johnson, the brother of former foreign secretary Boris Johnson, last week.

Some ministers have suggested May should call the bluff of the EU by walking away from the negotiating table altogether. But perhaps one of the most revealing comment on the current state of Brexit was made on Tuesday not by a politician, but by BBC political correspondent Chris Mason during a live television broadcast.

"People like me are paid to have insight, foresight and hindsight, and to be able to project where we are going to go," he said. "To be quite honest, looking at things now, I haven't got the foggiest idea what is going to happen in the coming weeks."