Scotland's leading politician is clashing with Britain's former treasury chief in a television debate meant to sway undecided voters in the final weeks before a poll on whether Scotland should become independent.

The televised contest is the first of two debates and pits Scotland's First Minister Alex Salmond against Alistair Darling only six weeks before the Sept. 18 vote.

Polls have consistently shown greater support for staying in the union, but the distance between the two sides has narrowed.

The high-profile debate was arranged after lengthy negotiations. Salmond had initially insisted that any debate should be against British Prime Minister David Cameron — but the Conservative leader refused to take part.

Exchanges quickly grew heated, and centered on whether Scotland would be able to keep the pound as its currency.