It has felt at times like the only TV debate in the referendum campaign has been about whether there would be a TV debate.

Alex Salmond said he would only appear if he could appear with the Prime Minister, then both sides spent time wrangling over when the confrontation would take place.

Eventually, however, a date was agreed and the first debate, between Mr Salmond and Alistair Darling, the leader of Better Together, will go ahead tomorrow at STV.

Loading article content

It will be a pretty tightly controlled affair, with the time each man has to speak strictly limited, although some will see Mr Salmond as the heavyweight contender from the start. He also won the toss of a coin giving him the right to speak first and last.

But how important are TV debates? Famously, in 1960, a slick John F Kennedy outshone a pale Richard Nixon in their televised debates. And at the last election, Nick Clegg's performance won him many votes.

Whether tomorrow's debate has the potential to have the same sort of effect is uncertain, but the lesson of political history is that TV debates matter. They can change minds and swing votes. Everyone should be watching.