Labour and the SNP clashed on the issue of knife crime as hostilities intensified prior to a key by-election in Glasgow.
The battle for Glasgow North East is still in the "phoney war" stage as no date for the contest had yet been set. But four main party candidates faced each other for the first time on Friday for a hustings meeting.
David Kerr for the SNP, Willie Bain for Labour, Ruth Davidson for the Conservatives and Eileen Baxendale for the Liberal Democrats, faced questions on issues ranging from tax, MPs' expenses and the cancelled Glasgow Airport Rail Link.
The clash on knife crime came when the candidates were quizzed on their view on mandatory jail terms for carrying a knife. Mr Kerr ruled out mandatory jail for carrying a knife, arguing judges had to have discretion in sentencing.
"I think there should be a presumption towards jail - but you have to give judges and sheriffs a degree of discretion," he said.
But Labour's Mr Bain, a law lecturer, retorted: "You've been speaking to judges, I've been speaking to people" before calling for mandatory jail terms for carrying a knife.
"I think a four-year sentence would be good," he said. "We are talking about people who are carrying blades, flick-knives. It's for this sort of thing we need to have tougher action."
The Tories' Ruth Davidson, meanwhile, said there should be a "presumption" for jail terms for carrying blades, but this should not be mandatory.
The Liberal Democrat's Ms Baxendale, a councillor and former social worker, said: "Mandatory jail sentences for carrying a knife - no. Mandatory jail sentences for using a knife - yes."
But Ms Baxendale later went on to commit the gaffe of the event when candidates were asked about their respective party leaders visiting the by-election campaign. Mr Bain said he would welcome Gordon Brown if he came, and Mr Kerr said Alex Salmond was in the constituency on Friday.
Ruth Davidson said she expected to see David Cameron and Ms Baxendale said she expected to see Nick Clegg and Nicol Stephen, even though the Scottish Liberal Democrats are now led by Tavish Scott.
The Glasgow North East seat became vacant with the resignation of Speaker Michael Martin.
