Key London demands set to be overlooked in withdrawal paper

The British government and European Union could be on a fresh collision course over Britain's exit from the bloc, when the EU publishes its latest draft Brexit divorce treaty on Wednesday.

The 120-page document aims to finalize a withdrawal deal agreed in principle after lengthy negotiations last December by British Prime Minister Theresa May and European Commission President Jean-Claude Juncker.

EU negotiator Michel Barnier insisted there are "no surprises" in the draft but added it would take a strong line on issues "on which there has been no progress since December, which is a matter of concern for me".

It is believed this could mean it overlooks some of May's key demands on issues such as the nature of Britain's post-Brexit transition period, citizens' rights and the Irish border.

The issue of the post-Brexit border between Northern Ireland - a part of the United Kingdom - and EU member state the Republic of Ireland is a particularly challenging one.

Unless an agreement can be reached on how to guarantee undisturbed ties between the two territories, there is the possibility of a hard border being reintroduced 20 years after the Good Friday Agreement, which brought an end to generations of sectarian violence known as The Troubles, a suggestion that has been greeted with dismay on both sides of the Irish Sea.

Barnier has gone as far as to say that if no better solution can be found, a "backstop" would be introduced, keeping Northern Ireland in full alignment with the EU's customs union and single market.

The UK government opposes such an idea, fearing that it would effectively be introducing a sea border between Northern Ireland and the rest of Great Britain.

Another contentious issue is Britain's post-Brexit transition period, allowing access to Europe's single market in return for agreeing to abide by European laws, without any say in policymaking.

The draft document rules out any possibility of an "open-ended" transition, stipulating that any such period would not be allowed to continue beyond the end of 2020. A further stumbling block could be what rights are afforded to EU citizens who move to Britain during that transition period.

Following the outcome of the referendum on membership in 2016, Britain is due to leave the EU at the end of March 2019, so there is pressure on both sides for agreements to be reached. The draft document will also set out details of the severance payments Britain will have to make when it departs.

In addition to the draft being published, May will have talks on Thursday with European Council President Donald Tusk, before on Friday making a speech to set out her blueprint for post-Brexit relations between Britain and the EU.

Tusk has previously said that many of London's post-Brexit trade demands are "pure illusion", and earlier this week, opposition Labour Party leader Jeremy Corbyn put more pressure on May when he announced a policy change in favor of staying in a post-Brexit customs union with the EU.