The Metropolitan Police have said they are carrying out searches at properties linked to Peter Mandelson in Wiltshire and north London as part of their investigation over allegations of misconduct in public office.
The police launched an investigation into the ex-Labour minister on Tuesday after suggestions he passed on market-sensitive government information to convicted sex offender Jeffrey Epstein.
In a statement, the force said: "He has not been arrested and enquiries are ongoing."
Lord Mandelson has not responded to requests for comment but the BBC understands his position is that he has not acted in any way criminally and that he was not motivated by financial gain.
He has previously expressed his regret for his continued association with Epstein and apologised "unequivocally to the women and the girls who suffered".
