EDINBURGH (Reuters) - Scotland’s Brexit minister believes there is a “pretty strong” chance Britain will leave the European Union with no deal, but that the UK government could collapse before then.

FILE PHOTO - The Union Flag and a European Union flag fly near the Elizabeth Tower, housing the Big Ben bell, during the anti-Brexit 'People's March for Europe', in Parliament Square in central London, Britain September 9, 2017. REUTERS/Tolga Akmen

Michael Russell said the devolved pro-independence Scottish administration is trying to prepare for Brexit, despite Scots having voted against it, but possible outcomes are “legion”.

“I think the chances (Brexit) happens without an agreement are still pretty strong, that there will a crashing out,” Russell, who is heading Scottish Brexit talks with the UK government, told Reuters.

“It is also distinctly possible (...) that the government will fall and there will be another election or another government will come in,” he added.

British Prime Minister Theresa May is running a minority Conservative government, kept in power by a Northern Irish Protestant party.

Russel said it was unclear what any new government might do.

“Will it start negotiations afresh, what will be its mandate, what will it be negotiating for?” Russell said, describing his frustration with the process and its uncertainty.

Britain’s vote to leave the EU has divided the main parties over what new relationship it wants with the trading bloc after 40 years of shared ties.

It has also strained the ties of the UK’s four nations, because Scotland and Northern Ireland voted to keep EU membership while Wales and most-populous England voted to leave.

On key issues, such as the set-up of powers devolved beyond London’s parliament after Brexit and the need for fluid EU immigration, Edinburgh’s Scottish nationalist administration is at loggerheads with the Conservative UK government in London.

Earlier on Wednesday, Britain’s First Secretary of State Damian Green said Britain believes no deal is very unlikely but was readying contingency plans just in case. As recently as Tuesday, the UK’s Brexit Minister David Davis said Britain was ready to walk away with no deal.

“If we leave without a deal, we have to look at whether there will be democratic legitimacy in that, how would that be confirmed. Would (Britain’s parliament) accept that we leave without a deal? I think that’s unlikely in its present composition,” said Russell, whose formal title is Minister for UK Negotiations on Scotland’s Place in Europe.

Russell described Brexit as the “existential threat to Scotland’s future” and said his government was preparing, to the extent that it could, for all options regarding Brexit. For that reason, he argued, Scotland should be offered a new choice which might include independence from the UK -- rejected by Scottish voters in 2014 by a 10 percentage point margin -- once it is clear what Brexit means.

“At some stage the people of Scotland will have to be asked whether they want to stay with something which is completely disastrous and will not produce a good result, of that I have no doubt, or whether we do something else,” he said.

In a June general election Russell’s Scottish National Party suffered heavy losses - albeit from a very high level - and was forced to withdraw its offer of a new independence referendum as a result.