Scottish Labour should brace itself for the loss of every constituency seat at Holyrood next year, senior party insiders have privately warned.

They predict the party will struggle to recover from its thumping in the General Election in time for next May's Scottish poll.

One said: "We have to assume we won't win any of the constituency seats in the Scottish Parliament election and that has to be the basis of our strategy."

Such a defeat would still leave the party with some MSPs at Holyrood - thanks to the additional member 'top up' list.

MSP Ken Macintosh, meanwhile, launched his leadership campaign saying that he was "realistic" about Labour's chances.

Former leader Johann Lamont has backed the current frontrunner in the race Kez Dugdale.

Labour tumbled from 40 MP's to just one last month after the SNP took 56 out of 59 seats in Scotland, with the Nationalists taking 50 per cent of the vote, Labour 24 per cent and the Conservatives 15 per cent.

Eastwood MSP Mr Macintosh said his first priority would be to make the party "less tribal" and more willing to work with others, including the SNP.

While he said it would be "artificial" to set a combined constituency and list seat target, he admitted: "I'm realistic about where we are, I'm realistic about Labour's chances. We've just had a terrible defeat.

"My aim over this year is to be a constructive opposition."

Mr Macintosh also said he was confident he would win enough nominations from the party's MSPs and European and Westminster parliamentarians to allow him to stand.

Ms Lamont, who quit last year to be replaced by Jim Murphy, said Scottish Labour's deputy leader could give the party "a strong and modern voice".

Ms Lamont dramatically quit last year accusing the UK Labour of treating Scotland like a "branch office".

Ms Lamont warned that Murphy's successor had to be a "long-term, long-haul appointment".

She said: "Scottish Labour is still in shock and we have many questions to ask of ourselves, arguments to reflect on and changes to make. That will not be done quickly and cannot be for elected politicians alone.

"Electing a new leader will not be enough but the right leader, supported and encouraged, can guide and drive that change.

"It is hardly the easiest of jobs. Indeed, I have reflected that too often our party comes together to elect a leader and then steps back, arms folded, waiting to be disappointed."