91Èȱ¬

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 4x100 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.

The British Olympic Association said it welcomed Ujah's "contrition" but added: "This should act as a salutary message for anyone - British or otherwise - who is doping or considering doping as a way of boosting their athletic performance. You will get caught. You are not welcome on our team and nor are you representative of our values, or of our nation."

Ujah did not challenge the decision over his violation, which was made by the Anti-Doping Division of the Court of Arbitration for Sport (Cas).

Cas requested World Athletics - the sport's governing body - should consider its own actions, including the possibility of handing Ujah a ban from competition.

The UK Anti-Doping website states ostarine is "not approved for human consumption in the UK or anywhere else in the world", adding the substance is designed to have similar effects to testosterone in that it can aid muscle-building.

Both Ostarine and S-23 are known as selective androgen receptor modulators (Sarms).

US Anti-Doping (Usada) says Sarms have "similar anabolic properties to anabolic steroids".

The Usada website offers athletes access to the Global Dro website where substances can be searched in order to check on regulations.

S-23 is listed as an anabolic agent and prohibited both in and out of competition.