'It seems to be a very self-centred and rather spiteful piece of work. I hope we don't see him in the House of Lords again.'
Lord Morgan, Labour historian
'It is a warning to everyone in the future that they shouldn't even exchange a casual joke, let alone a confidence, because it is plainly all going to be regurgitated for the delight of our political enemies and the bank account of the writer. It changes the whole currency of the internal politics of a party and a government. It doesn't add anything to any historical understanding. As far as I can see, this autobiography is retailed gossip. There is certainly no big picture. Mandelson is a creative spirit, but this caricature of the Prince of Darkness was developed, and Peter inhaled it. He seems to believe that the cartoon was an oil painting.'
Lord Kinnock, who employed Mandelson as his Director of Communications
'Gordon Brown, for all his tantrums, comes out as the sanest of the three.'
Ken Livingstone, former Mayor of London
'I didn't like him at all. I thought he was a very devious fellow.'
Lord Healey, former Labour deputy leader
'I haven't read the book. I have no intention of reading it. Why would I want to? He seems to have lost the plot.'
Charlie Whelan, former spin-doctor to Gordon Brown
'The whole period seems to reflect a period of complete emptiness; New Labour, political precocity. Mandelson is a bright man, but he has spent too much time in the dark plotting against everybody. His revisionism nearly destroyed the Labour Party.'
Mark Seddon, former editor of 'Tribune'
'History doesn't belong to the victors, it belongs to whoever writes it up. Mandelson is getting his retaliation in first.'
Paul Staines, Guido Fawkes blogger
'He is his own worst spin-doctor. He seems to have offended just about everyone. I think this is sad and damaging to Peter, not just to the Labour Party.'
Ed Miliband, Labour leadership contender
'Peter loves the spotlight but it's time to leave the stage.'
Andy Burnham, Labour leadership contender
'My advice to people would be to read more serious books.'
Clare Short, former Labour Cabinet Minister
'These diaries are highly personalised, sensationalised and self-promoting, and totally bereft of ideology. It's all childish tittle-tattle.'
Michael Meacher, Labour MP
'It's tired drivel. I think I read half a sentence and then started to think of other things. Miles and miles of FA. Like a Chinese meal, he strings a lot together and then it's just air. All he has is superficiality. I see the panic of someone who has lost his main source of income. I'm paralysed with indifference.'
Paul Flynn, Labour MP
'He gives good advice to others in terms of handling oneself and the media, but he doesn't apply that same logic to himself.'
Brian Donohoe, Labour MP
'He was pretty treacherous and this just proves it.'
Clive Efford, Labour MP
'I think he's having a laugh.'
Mike Hancock, Lib Dem MP
'It's well timed, I'll give him that. He knows releasing them now will make him a good chunk of money – perhaps he'll declare it or perhaps not.'
John Hemming, Lib Dem MP
'Why do people have to do it?'
Brian Iddon, former Labour MP
'The people at the top may feel the need to publicise their squabbles but the people who end up suffering are the volunteers, the staff, the supporters who work tirelessly for very little thanks.'
Jane Kennedy, former Labour MP
'It always shocks me, the haste with which people try to rush these things out.'
Jim Knight, former Labour MP
'The publication of the memoirs confirms in my view that he was, is and always will be a complete shit. His motives were money and the urge to see his name in lights again. He's now off to spend time with the rich and well connected, who he feels much more comfortable around.'
Ian Davidson, Labour MP
'What Peter Mandelson says is that we have to learn lessons. The most important lesson is that we have to move on beyond Peter Mandelson.'
Wayne David, Labour MP for Caerphilly
'Why on earth would you read anything that Lord Mandelson has said? You simply know it will be a lie. The man spews out complete fabrication and is chronically and pathologically incapable of telling the truth.'
Godfrey Bloom, UKIP MEP
'They should really be subtitled Mandy's Misery Memoirs. What we hadn't realised was that this was a whole Princess Diana situation, that there were three people in the marriage. Everybody in the Labour Party will be reading this with two emotions: sheer horror, and absolute determination never to let this happen again.'
Stephen Pound, Labour MP
'I haven't read it, and I won't read it. I've got better things to be doing with my time.'
Roger Godsiff, Labour MP