In the email to Powell – the current UK government’s national security adviser – Lord Mandelson refers to Epstein as “safe”.

The email on 7 May 2002 states: “Do you remember when Clinton saw TB [Tony Blair] he said he wanted to introduce his travelling friend, Jeffrey Epstein, to TB?

“This was frustrated – TB said at the time – in the office for reasons (he says) he was unclear about. I think TB would be interested in meeting Jeffrey, who is also a friend of mine, because Jeffrey is an active scientific catalyst/entrepreneur as well as someone who has his finger on the pulse of many worldwide markets and currencies.

“He is young and vibrant. He is safe (whatever that means) and Clinton is now doing a lot of travelling with him.”

The email continues: “I mentioned to TB that Jeffrey is in London next week and he said he would like to meet him.

“I have ascertained from Jeffrey that he is flexible – he could be here any time from Tuesday onwards to fit round the diary – but would obviously need to know reasonably quickly so as to re-schedule accordingly. Can you let me know?”

There are three separate handwritten notes on the print-out of the email, some of which are illegible, but one appears to read “do you want to do this… Because you wanted to see Clinton by yourself… I know very little more about him”.

At the time, Lord Mandelson was a backbench MP, having twice resigned from the cabinet, but still a force in Labour.

Clinton has acknowledged being a former associate of Epstein but said had no knowledge of his crimes.