So when CHI was asked by its client The Times to create an ad campaign promoting the paper's serialisation of Mandelson's memoirs, the creative approach was clear.
The ads (hardly award-winners, but surprising in their humour) ran on TV last week and featured Mandelson reading a story about a kingdom "run by two powerful kings" and a third man, "the people called him 'the Prince of Darkness' ... don't know why".
One week on and Mandelson's 'The Third Man' is at number two in the Amazon bestseller list, and The Times has enjoyed a healthy boost to its daily sales figures.
Campaign quizzed Mandelson about the campaign.
Peter, are you surprised the ads have been so talked-about?
Well, I've never been stopped in the street so often before. People really want to talk to me about the ads.
Was it hard to allow yourself to be shown in such a tongue-in-cheek way?
Once I got over the shock, it was fine – and I didn't have to wear ermine, thank goodness – it was a hot day. The team were very professional and it was a lot of fun. Politicians should be prepared to send themselves up sometimes.
Is it true about those bedtime stories to the Hornby offspring?
Oh, yes, and it's typical of Johnny to make a leap like that from reality to a piece of entertaining content.
You used to be an advisor to CHI's board. Do you like advertising?
Yes, I do – it's sharp, competitive and creative, public-facing and combines communication, art and messaging in a sophisticated mix. I've been doing that in politics in one form or another all my life. But I don't have any plans to get involved right now and, no, Johnny hasn't tried to tempt me back to CHI.
Wouldn't your expose of Labour have been as successful even without the ads?
The ads have made a real difference. It's been like lighting the blue touchpaper, building expectation and anticipation and amusement.
And what have your former colleagues made of it all?
Some of my colleagues haven't seen the amusing side, but then they don't know about advertising and about how to capture the public's imagination and make them smile.
MEDIA REACTION TO MANDY AD
The "Prince of Darkness" ads have been spoofed mercilessly since their launch, with Alistair McGowan and Aleksandr the meerkat among the funniest take-offs.
While editorial coverage of the spots has been mixed, the ads have certainly proved the PR value of their star – they were aired on Channel 4 News, the BBC breakfast show and GMTV, and even discussed on 'Question Time'.
Various newspapers also covered the campaign, including The Daily Telegraph, which called it "a magnificent new landmark in ex-ministerial camp". It even made The Spectator's front page.
Twitter has also been rife with commentary, with some Tweeters calling it "sublime" and others veering towards a more "ridiculous" verdict.
According to estimates, The Times' circulation was boosted by around 100,000 copies during the serialisation.