Pakistan's Mohammad Aamer has been released from a British jail after serving half of a six month sentence for his part in a spot-fixing scam.

Aamer, 19, was free from Portland Prison in Dorset, south-west England, on Wednesday morning UK time, Britain's Press Association reported.

The teenage fast bowler, one of the most promising young players in world cricket, was one of three Pakistan cricketers who received prison terms at London's Southwark Crown Court in November over their roles in a plan to bowl deliberate no-balls during a Test against England at Lord's in 2010.

Former Pakistan Test captain Salman Butt, 27, was sentenced to two and a half years for his role as the "orchestrator" of the scam while seamer Mohammad Asif, 28, received a 12-month prison term for delivering one of the fraudulent no-balls.

Mazhar Majeed, 36, the London-based sports agent who organised the scam was jailed for two years and eight months.

All three players are also serving five-year bans from cricket imposed by the International Cricket Council (ICC).