Mr Mandelson may regard himself as master of the arts of political guile - but he has created many dangerous enemies along the way.
They range from Cabinet ministers to lowly Labour backbenchers, all of whom claim to have reasons to loathe the man who, ironically, did more than most to restore the wreckage of the Labour Party in the 1980s to its overwhelming supremacy today.
He himself has admitted that he inspires dislike among his colleagues. "I have made enemies, possibly unnecessarily and I regret that," he said in 1997 after failing to get elected to Labour's ruling National Executive Committee.
Mr Gordon Brown, Chancellor of the Exchequer, has probably never forgiven Mr Mandelson, whose king-making efforts ensured that Mr Tony Blair became Labour's leader in 1994, when Mr Brown had always been seen to be Mr John Smith's natural successor.
Mr Mandelson, in a famous letter to Mr Brown said that if "Tony felt he had to stand, and you did too, what would be the consequences? I think you both and our cause and the party would all be hugely damaged..."
He said it would be difficult "for Tony to withdraw in your favour" and suggested that Mr Brown should "implement a strategy to withdraw with enhanced position, strength and respect".
This was seen by commentators at the time as subversive and clearly calculated to undermine Mr Brown's position. Significantly Mr Brown did not reply to the letter.
Mr John Prescott, the Deputy Prime Minister, is said to dislike Mr Mandelson.
He remains one of the few members of the Cabinet who still uses the word "socialist" with pride and he loathes everything to do with spin-doctoring and image-making - the two issues with which Mr Mandelson is so closely identified.
Although Mr Prescott backed Mr Mandelson for the Labour Party communications post in the 1980s, he was soon to find he was - as he claimed - a victim of Mr Mandelson's activities.
On TV, Mr Prescott later accused Labour's advisers of trying to rubbish him. He singled out Mr Mandelson, saying he had "extraordinary influence beyond what he should have exercised".
But Mr Prescott's apparent contempt for him was most spectacularly demonstrated in 1997, when Mr Prescott was shown a crab which had been fished out of the River Thames. He addressed the crab with the words "Hello, Peter."
Mr Mandelson said he was "amused and relaxed" by Mr Prescott's remark.
Mr Robin Cook, the Foreign Secretary, cannot be enamoured with Mr Mandelson, either. In recent months the word had been going about Westminster that Mr Mandelson would very much care to become Foreign Secretary himself.
Dr Mo Mowlam, Cabinet Office Minister, claimed that during the Good Friday Agreement sessions she had, as Northern Ireland Secretary, been reduced to the role of tea-lady. While she was still in the post, Mr Mandelson was letting it be known he would be the next supremo at Stormont.
When in Opposition, the two had a spat when Mr Mandelson interrupted her 10 times during a Commons speech.