Nicola Sturgeon, the Deputy First Minister, has expressed regret over a notoriously ill-tempered television exchange with Scottish Labour leader Johann Lamont at a Fringe show yesterday.

Ms Sturgeon, appearing at the All Back to Bowie's show at The Stand in St Andrew's Square, was involved in a fractious TV debate with Lamont on STV's Scotland Tonight special in February.

Yesterday Ms Sturgeon, interviewed on stage by the playwright David Greig, said: "Inevitably these debate are adversarial, that is how they are set up to be. Probably my least favourite part of the campaign to date has been that debate I did with Johann Lamont.

"Both of us - we have spoken about it - if we could turn the clock back, we would try to do that very differently. Whether we would succeed or not, I don't know, because the way the debate was set up, it was designed to make it like that. I much prefer doing public meetings, because you can engage in a debate that is more nuanced, you can get into arguments that is much more about addressing people's genuine concerns."

The STV debate involved some angry exchanges, with both Ms Sturgeon and Ms Lamont talking over one another.