Scotland's First Minister Nicola Sturgeon has insisted she is not bluffing about the prospect of a second Scottish independence referendum.
She hinted that a "hard" Brexit could see a vote on independence within five years, but insisted that she was offering a "compromise solution" to the British prime minister.
Ms Sturgeon has indicated that a "soft" Brexit could take the issue of a second referendum on Scottish independence off the table in the short term.
But speaking on BBC One's Andrew Marr Show she said she was prepared to call a fresh vote if the terms of Brexit were not right.
She said, "they will be making a big mistake if they think that I'm in any way bluffing" because leaving the European Union created a "fundamental question" for Scotland.
"If we're going to be ignored, if our voice has been completely cast aside, our interests cast aside, then that can happen on anything," she said.
"And we have to ask ourselves in Scotland are we happy to have the direction of our country, the kind of country we want to be determined by a right-wing Conservative government perhaps for the next 20 years, or do we want to take control of our own future.
“And that's the case that in those circumstances I think it would be right for Scotland to have the opportunity to decide."
Asked if she was looking at a referendum "much quicker" than in five or ten years' time if there was a hard Brexit she said: "I would think, yes. But let me not get away from this point, I'm putting to Theresa May a compromise solution."
But the First Minister was critical of Ms May's approach to the issue and co-operation with leaders of the devolved administrations.
She said that instead of "prioritising " the "sensible solution" of keeping the UK in the single market, Ms May was trying to "appease" Eurosceptics in her "deeply-divided" party.
Voicing concerns about the Prime Minister's approach to the process, she added: "If the UK's coming out of the European Union that has enormous implications for Scotland as it does for other parts of the UK, it has enormous implications for our economy, for jobs, for living standards, for trade, investment, for the kind of society we are and I want to play my part in making sure we get the right outcome from that.
"That's why the Scottish Government has published proposals that we hope are taken seriously, but thus far almost two-thirds of the way to the triggering of Article 50 we know no more about the UK's position than we did the day after the referendum and that is increasingly unacceptable."