The former senior Labour figure Peter Mandelson faces a fixed-penalty notice after being caught urinating in public, it has emerged.

Mandelson was photographed in the act while standing outside the home of the former chancellor George Osborne last November, shortly after he had been sacked as the UK’s ambassador to the US over his relationship with the convicted child sex offender Jeffrey Epstein.

The Royal Borough of Kensington and Chelsea has said it intends to issue a fixed-penalty notice of £300 – reduced to £150 if paid within 14 days – for the offence. But officials have not yet done so because, five months on, they are still struggling to find Mandelson’s address.

The incident happened after Mandelson had visited Osborne for dinner following his removal from the Washington post. The pictures were first printed by the Daily Mail, which reported that Mandelson had been seen urinating at about 11pm, having arrived at Osborne’s £10m home three hours earlier with a bottle of Chilean wine. At the time, he offered “profuse apologies”, telling the paper: “There is no disguising my embarrassment.”

Mandelson later addressed the incident in an interview with the Times, saying: “People said it was very humanising. I didn’t quite feel that myself.

“I just blame Uber. I had two cars, both of which cancelled on me, and after half an hour I was bursting for a pee. I could have gone back and woken them all up, but they did have three children [there]. The real question is, how on earth was there a photographer who got me as I was arriving, and was still there at 11 o’clock at night?”

Mandelson has come under intense pressure since files on the Epstein case, released in batches by the US Department of Justice, showed he had stayed in touch with the now late Epstein after his first conviction in 2008.

Documents appeared to show Mandelson passing confidential government information to the disgraced financier at the height of the global financial crisis, while he was serving as business secretary under Tony Blair’s successor, Gordon Brown.

He was arrested at his London home in late February as part of an investigation into whether he leaked Downing Street emails and market-sensitive information. He has denied any wrongdoing and no charges have been brought.

That arrest followed a tipoff from the Commons speaker, Lindsay Hoyle, that Mandelson was planning to flee to the British Virgin Islands. Police later released him from the bail conditions they had imposed after deciding he was not a flight risk.

Speaking at the time, Mandelson’s lawyers said: “Our client did not and does not pose a flight risk and will continue to cooperate with the police investigation. He will not be making any further comment at this stage.”