Gammer suffered his second professional defeat on Saturday

Gammer, 30, decided to quit after losing to John McDermott on Saturday in an eliminator to face current British champion Danny Williams.

"The time is right for him to retire," Gammer's manager Paul Boyce told BBC Wales Sport.

"He feels he hasn't got the desire to continue but I'm very proud of what he has achieved in the ring."

Gammer lost his British crown to Danny Williams last March, but he took his first steps on the road back to a title shot with a workman-like points win over Paul King in June.

His hopes of regaining his belt were dashed on Saturday, though, when a below par performance resulted in a 98-93 points defeat to McDermott in Sheffield on Saturday.

"Even before the Danny Williams fight, I didn't things were quite right with Scott," added Gammer.

"John McDermott is the type of fighter Scott would normally stop in six or seven rounds so we've come to a mutual agreement to call it a day."

Gammer become the first Welshman to win the British heavyweight title in 22 years when he beat Mark Krence last year.

The Pembroke Dock man bows out of the sport with a record of 18 wins (9 KOs), two defeats and a draw.