The fingernails could catch on.

Eddie Izzard yesterday brought colour and panache to the referendum debate, which has so far been a grey discussion about statistics, treaties and export figures and has left many voters disengaged as a result.

His flamboyant talons, painted as the Union Jack and the EU flag, are not something ever likely to be sported by Alistair Darling, Willie Rennie or even Annabel Goldie (though one never knows) but they may catch the public imagination. When it comes to engaging voters, nail varnish may speak louder than Treasury reports.

Two questions arise from the comedian's visit: will it help boost Better Together's fortunes? And does it improve the quality of the debate to have celebrities, especially those who cannot vote in the referendum, campaigning for either side?

Only the polls will show whether Izzard has helped the pro-UK cause, but his comments prior to the gig demonstrated a marked shift away from hardline issue-bashing, even though Izzard, a fearsomely bright and seasoned political campaigner, could almost certainly have tackled them if he chose. Instead, he referenced the bloody medieval conflicts between England and Scotland, and noted that it was "beautiful" to have reached a position of being together. He stressed that "we are all the same people", a sense heightened for him by running multiple marathons around the UK for Sport Relief. It was a simple, heartfelt, positive message of the sort that has been woefully lacking from the No camp. Is this the magic formula that will move the masses? Even a professional pollster with a sideline in astrology would struggle to predict that, but with warnings about the risks of independence leaving many key voters cold, this change of pitch from Better Together is to be expected.

Does it trivialise the debate to have it fronted by celebrities? Izzard, it must be said, is no political lightweight, with his long history of Labour party support; he has spoken seriously of standing for office. In a nation of monoglots, arguably anyone who can perform a gig in French and German (Izzard passionately believes humour transcends frontiers) deserves respect. All UK residents, famous or otherwise, will be affected by the outcome of the referendum and have the right to voice their opinion. That does not mean, though, that Scottish voters will pay them any attention.

A certain amount depends, of course, on what a celebrity has to say - and how they say it. There is certainly a crying need for more comedy in what has so far been a humour-free zone. Susan Calman and Rory Bremner have dipped their toes in the water, as if into a pool of piranha, and been chastened by the experience, while Billy Connolly has decided to steer well clear. And they are all Scots. So Izzard, a self-professed "Englishman called Edward", certainly has guts.

Voters are highly unlikely to be swayed merely by the say so of a celebrity, nor should they be, but if Izzard's visit marks a shift into more positive campaigning by Better Together, then he is doing the whole debate a favour.