Great Britain have been stripped of the silver medal won in the 4x100m relay at last summer’s Tokyo Olympics after team member CJ Ujah was found to have committed a doping violation.

The British team finished second to Italy by one-hundredth of a second.

Ujah tested positive for ostarine and S-23 after the event on 6 August.

The 27-year-old says he “unknowingly consumed a contaminated substance” and the situation is one he “will regret for the rest of my life”.

Ujah was joined in the 4x100m relay team by Zharnel Hughes, Richard Kilty and Nethaneel Mitchell-Blake.

London-born Ujah added: “I would like to apologise to my team-mates, their families and support teams for the impact which this has had on them. I’m sorry that this situation has cost my team-mates the medals they worked so hard and so long for, and which they richly deserved. 

“I would also like to apologise to both British Athletics and Team GB. British Athletics has supported the relay athletes for years and this has been difficult for everyone involved in the programme. 

“Representing my country at a second Olympic Games surpassed my childhood sporting ambitions and I will forever be devastated that this situation has marred the success achieved by the men’s 4×100 relay team in Tokyo.”

The loss of the silver means Great Britain’s medal tally at the Tokyo Games falls to 64, one fewer than the team achieved at London 2012.

It is only the third time Great Britain have lost a medal at a summer or winter Games. 

Judoka Kerrith Brown at the 1988 Seoul Games and skier Alain Baxter at Salt Lake in 2002 both lost bronze medals after testing positive for a banned substance.