Lord McConnell’s claim came as the SNP extended its lead over Labour and is now threatening to virtually wipe out the party in Scotland, according to a new opinion poll.
Backing for the Nationalists has increased by three per cent to 48 per cent – a result that would give Nicola Sturgeon’s party 53 of the 59 Westminster seats in Scotland.
The Panelbase poll put Labour on 27 per cent, with the party’s support falling by two points in the last three weeks in Scotland.
Lord McConnell said the defeat of a whole group of talented Labour politicians in Scotland would be a huge loss for the country and the party.
He said: “We have some excellent new candidates in this election. They would make fantastic MPs, fighting for fairness and justice. It would be a tragedy if this protest movement based on the past got in the way of our chance to elect these people as MPs for the future.”
Labour would take just five of the 41 seats it held in Scotland in 2010 if the results of the Panelbase survey of more than 1,000 voters were replicated on 7 May.
Meanwhile, 16 per cent said they will be voting Conservative, four per cent back the Liberal Democrats, three per cent support Ukip and two per cent will vote Green.
The Liberal Democrats could lose all but one of the 11 seats they won five years ago, while Scotland could have no Conservative MPs.
Panelbase questioned 1,044 voters in Scotland between April 20 and April 23.
However, Lord McConnell, who was first minister from 2001 to 2007 before being ousted by Alex Salmond, said: “I completely understand why thousands of people in Scotland who were not traditional supporters of independence voted Yes.
“There were times when I was angry at the No campaign, too.”