A British boxer rated as a good bet to win Olympic gold has flown home from Beijing after failing to make his fighting weight.

Frankie Gavin, 22, is said to be "completely devastated" at his failure to slim down sufficiently to fight in the lightweight category at the Beijing Games.

The head coach of Great Britain's boxing team, Terry Edwards, said: "Frankie has been working his whole boxing career towards the Olympic Games and he is obviously completely devastated.

"Whilst the support staff down in Macau and I, have done everything we could, regrettably it is clear that Frankie will not make his weight before tomorrow morning's weigh-in."

Edwards insisted he took the agonising decision to pull out Gavin because of serious fears for his fighter's health.

But the timing of the withdrawal is bound to be questioned with Gavin's battle to make the weight having been well documented long before he became Britain's first world amateur champion in Chicago in November.

Amateur Boxing Association chief executive Paul King said: "ABAE will launch an internal investigation into the circumstances leading up to this withdrawal, which is a massive blow to our gold medal hopes, and to our essential UK Sport and lottery funding.

"I am very disappointed on behalf of the ABA of England, who no longer have direct international contact with Frankie as he now boxes under the GB programme and the guidance of head coach Terry Edwards."

Edwards defended the timing of his decision, insisting Gavin had to be given every chance to hit the target until it became evident that even if he had tipped the scales at 60kg it could prove detrimental to his health.

Edwards said: "Frankie has been struggling at the weight all year but we were confident he would get it down. He struggled to make the weight at the world championships in November but went on to make history.

"It was obvious to me that Frankie was empty and I had the thankless task of telling him it was over. I felt if I pushed it any further there would have been a serious health risk.

"It was the hardest decision I have ever had to make in boxing. But Frankie was completely dried out. It got to the stage where even if he had somehow managed to make weight in time, it was going to be detrimental.

"I can categorically deny there is anything mysterious or unusual about the circumstances surrounding Frankie's withdrawal. There is bound to be speculation but the simple fact is that these things happen in boxing."

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