Scotland's pro-independence leader Alex Salmond won a final TV debate on Monday just over three weeks before a historic breakaway referendum, but it wasn't clear if his combative performance would help him catch up in the polls.

In a bruising debate before the Sept. 18 referendum, Salmond relentlessly talked over and at Alistair Darling, the leader of the Better Together anti-independence movement, and it was sometimes hard to hear what was being said.

With the campaign to break up the United Kingdom and sever Scotland's 307-year union consistently trailing in opinion polls by an average of up to 14 percentage points, Salmond's supporters were looking for a game-changing performance after he failed to sparkle in the first such encounter.