Labour had no economic policy and was not convincing in the eyes of voters during the election campaign, former chancellor Alistair Darling has said.
The senior figure, who stood down as an MP at the general election, said the party is now in a worse position than 1992 as the future of the country is at stake.
He insisted Labour had also failed to defend its record in government, adding it was “absolute rubbish” when some effectively conceded they had achieved nothing in 13 years.
Asked what he believed was missing from his party’s message, Mr Darling told BBC Radio 4’s Today programme: “We were not convincing.
“We did not have an economic policy. We didn’t repudiate the criticisms the Tories were making of when we were in government.
“They were occasions when we almost said we didn’t do any good in 13 years, which is absolute rubbish.
“You’ve got to have confidence about what you did in the past just as the courage to admit where you got things wrong – but we just didn’t look compelling and convincing.
“I lost count of the times when people looked at us and said, ‘Well, you know, I’m not sure, I’m not convinced’.
“These are people who always voted Labour in the past and many of whom took their votes elsewhere.”
Mr Darling, who previously represented Edinburgh South West, said people avoided making eye contact with him on the doorstep.
He said: “I walked down Gorgie Road in the heart of the city centre and I was struck by the fact people just looked away and when that happens you are done for.
“The last time that happened was in 1992. I’m afraid we are back there in political terms only worse because the future of our country, of Scotland in my case, the United Kingdom as well, is at stake.
“The Labour Party has got to get itself back on its feet and have a powerful argument about what we’re going to change and do and let’s see who can do that, but we also need to make sure we get the arrangements within the UK right – we can’t wait five years to do that.”
Mr Darling, who led the campaign against Scottish independence, said he favoured a longer leadership election contest in order to assess the candidates and “see what they’re made of”.
He said: “An awful lot of people being talked about now were only elected five years ago and you’ve got to see where they stand.
“But the big thing is what is our argument going to be for this parliament and an election which won’t be held possibly for five years?
“What do we want to see change? We had an argument when Tony Blair won in 1997. This isn’t about a beauty contest, it’s about ideas, it’s about what is relevant for the second decade of the 21st century.”