As a trusty sidekick, Baldrick always had Blackadder's back. Yesterday actor Sir Tony Robinson had the backs of Norwich's Labour candidates on a visit to the Norwich.

It was a fitting afternoon for the former Time Team presenter as he was given a tour of the undercroft of the city's medieval Guildhall, where the oldest part of the building dates back to 1407.

Labour parliamentary candidate for Norwich North, Jess Asato, said: 'Tony is someone who is passionate about the history and the arts so it is great that he was here visiting the Guildhall which is about to be reopened to the public.

'It was Labour which opened many museums to the public for free in 2001.'

She added: 'I hope he has a cunning plan to expose the Tories' cuts to funding for local heritage and archaeology.'

Labour's Norwich South candidate, Clive Lewis, said: 'Since Ed [Miliband] took part in the debate on TV people who had low estimations of him have seen he's not as bad as some in the media make out.

'There's time to go in this election but things are looking good for Labour.'

Asked about the personal attacks on Labour leader Ed Miliband, Sir Tony jokingly said: 'I hope that they carry on as it doesn't seem to be doing them any favours. Ed's personal poll ratings have been rising since the debate and these attacks just show the Tories are on the defensive.'

Claims that the campaign has turned nasty came after defence secretary Michael Fallon said Mr Miliband had 'stabbed his own brother in the back' to lead Labour and was now 'willing to stab the UK in the back' by doing a deal on Trident with the SNP 'to become PM'.

Mr Fallon defended his personal attack on Ed Miliband, saying: 'This is the rough and tumble of politics.'