A Pro-Europe demonstrator joins a "March for Europe" protest against the Brexit vote result earlier in the year, in London, Britain, September 3, 2016. REUTERS/Luke MacGregor

LONDON (Reuters) - British Prime Minister Theresa May has no democratic mandate to pursue a ‘hard Brexit’ that would cut political and trade ties with the European Union, the Scottish National Party said ahead of its annual conference later this week.

Most Scots voted for the United Kingdom to stay in the EU, unlike their compatriots in England and Wales, and the SNP has said June’s result may re-open the case for another referendum on Scottish independence after 2014’s vote to stay in the UK.

Last week May said she would start two years of talks on leaving the EU by the end of March 2017, triggering several days of heavy falls in sterling, which finished the week at a 31-year low, 17 percent below its pre-referendum level.

Much of the fall has been driven by concern that May’s Conservative government favours a ‘hard Brexit’ which curbs migration from the EU, rather than a ‘soft Brexit’ which emphasises maintaining close economic ties.

Business groups spoke out against a ‘hard Brexit’ on Saturday, and on Sunday SNP chairman Derek Mackay described the Conservative vision as the “narrow-minded xenophobia” of “the most reactionary right-wing Tory government in modern times”.

“The Tories have no mandate to pursue the hardest of hard Brexits,” Mackay said in a statement on Sunday.

“They should also, without any further delay, guarantee the rights of EU citizens living in Scotland and the rest of the UK, and end the disgraceful use of human beings as bargaining chips,” he added.

Britain’s Telegraph newspaper reported on Saturday that the government was preparing to allow all 3.6 million EU citizens already in Britain to stay, but ministers have previously said this hinged on Britons’ rights to stay in other EU countries.

The SNP, which has controlled Scotland’s devolved government since 2007, starts a three-day conference in Glasgow on Thursday.