Scotland could not keep the pound if it became independent from the UK, billionaire investor George Soros has said.
Dubbed "the man who broke Britain" after profiting by selling sterling on Black Wednesday, the Hungarian-born investor said it would not be "actually practical" for Scotland to keep its currency if Alex Salmond's campaign for independence was to succeed.
Mr Soros, speaking at the European Council on Foreign Relations in London, said: "Scotland wants to remain a part of the (pound) sterling and Britain is creating obstructions to that.
"It would be a very difficult relationship and I don't think that Scotland becoming independent and yet remaining part of the sterling is actually possible."
The UK Government has previously ruled out a currency union with Scotland if it were to win independence from the UK in the forthcoming referendum.
Chancellor George Osborne, Chief Secretary Danny Alexander and shadow chancellor Ed Balls united in saying they would not support Scotland keeping the pound were the Scottish majority to vote "yes" in September.
Speaking at the launch of his new book, The Tragedy Of The European Union: Disintegration or Revival, the now-retired Mr Soros said: "The alternative would be for Scotland to seek membership of the European Central Bank and then it would be part of the eurozone.
"I think an independent currency would be very inefficient and potentially dangerous."
Mr Soros also described the crisis in the Ukraine as a "wake-up call" to Europe - and called on the union to concentrate on doing what was best for the EU as a whole, rather than focusing on the needs of individual member states.
He said: "Ukrainians have effectively proven they are willing to sacrifice their lives to be closer to a Europe that is at the same time in the process of disintegration.
"Europe now faces this issue. Are they going to respond to the invasion of Crimea based on their narrow national interests or are they going to act on a united basis representing the interests of the whole European Union?
"It is a challenge and I hope that Europe will respond to it and actually rediscover its original mission."
He also claimed that Russian President Vladimir Putin "outmanoeuvred Europe with no difficulty" in offering support to the Ukrainian people.
"I think Europe was totally unprepared for this crisis," he said. "Europe - as usual, true to form - and the German leadership demanded a lot and offered very little to the Ukraine.
"It was not difficult for Putin to come up with a better offer. Where Putin miscalculated was with the response to the Ukrainian public.
"He has a blind spot, it is beyond his comprehension and his expectations that a nation could actually have a spontaneous reaction.
"He believes somebody must have manipulated them. He believes the public can be manipulated therefore it is.
"This was an event where the public did react spontaneously and unanimously. It was a decisive moment for Ukraine because it established its identity as a country which wants to belong to Europe."