Three Pakistan cricketers and an agent were sent to prison in Britain on Thursday for their involvement in one of the biggest fixing scandals to tarnish the sport.

Former captain Salman Butt received 2½ years, the longest term of the three players. Mohammad Asif was sentenced to one year, while 19-year-old Mohammad Amir will serve six months.

Agent Mazhar Majeed was sentenced to two years eight months. All four may be released for good behaviour after serving half their terms.

The players were found guilty of conspiring with Majeed to bowl deliberate no-balls as part of a betting scam during the test match against England at Lord's in August last year.

It is the biggest fixing scandal in cricket since South Africa captain Hansie Cronje was banned for life in 2000 for taking bribes from bookmakers.

"It appears that the corruption may have been more widespread than the defendants here before me," said Judge Jeremy Cooke, who presided over the trial at Southwark Crown Court.

Cooke said the offences were "so serious that only a sentence of imprisonment will suffice to mark the nature of the crimes and to deter any other cricketer, agent or anyone else who considers corrupt activity of this kind."

"In Pakistan, where cricket is the national sport, the ordinary follower of the national team feels betrayed by your activities, as do your fellow countrymen in this country," Cooke said.

The quartet showed little emotion in the dock as the sentences were announced, remaining silent as they were led away from the courtroom to be taken into custody.

While Butt, Asif and Majeed are expected to begin their sentences at Wandsworth prison in south London, Amir is due to be sent to Feltham young offenders' institute in west London. Amir's lawyer, Henry Blaxland, said he intended to appeal.

The judge warned that cricket would be forever tainted by the latest scandal, which only emerged as a result of an undercover newspaper investigation.

"Now whenever people look back on a surprising event in a game or a surprising result, or whenever in the future there are surprising events or results, followers of the game … will be left to wonder whether there has been fixing and whether what they have been watching is a genuine contest between bat and ball," Cooke said. "What ought to be honest sporting competition may not be such at all."

Before sentencing, the chairman of the International Cricket Council's Anti-Corruption and Security Unit said the spot-fixing that occurred at Lord's was unlikely to be an isolated incident.

"It's certainly not rampant. It's certainly not indicative of rampant corruption of cricket," Ronnie Flanagan said. "I would have to say it is probably not absolutely isolated. It shows that we can never be complacent, we can never drop our guard, we must be ever vigilant and we will be ever vigilant."

The cricketers were caught after Majeed was recorded by an undercover reporter working for the now-defunct News of the World tabloid saying that the three Pakistan players had accepted money to fix betting markets by bowling three no-balls at pre-arranged times.

Majeed was secretly filmed accepting £150,000 ($242,000) in cash from the journalist.

Butt said he had ignored the requests from Majeed, his agent, and the 28-year-old Asif, who reached No. 2 in the ICC's test bowling rankings the month before the Lord's test, said he had only bowled the no-ball at precisely the time Majeed said it would be delivered because Butt had told him to run faster moments before bowling.

In sentencing Butt, Cooke said: "It is clear to me that you were the orchestrator of this activity, as you had to be, as captain, in arranging for these bowlers to be bowling the overs which were identified in advance to Majeed."

The judge also said Butt was "responsible for involving Amir in the corruption," describing the teenager as "unsophisticated, uneducated and impressionable."

"An 18-year-old from a poverty stricken village background, very different to your own privileged one, who, whilst a very talented bowler, would be inclined to do what his senior players, and particularly his captain told him, especially when told there was money in it for him and this was part of the common culture," Cooke said.

The 27-year-old Butt, Asif and Amir have already received lengthy suspensions from an International Cricket Council anti-corruption tribunal.

Butt was banned for 10 years, five of which are suspended, Amir was banned for five years and Asif was given a seven-year ban, with two suspended.

"'It's not cricket' was an adage," Cooke said Thursday. "It is the insidious effect of your actions on professional cricket and the followers of it which make the offences so serious.

"The image and integrity of what was once a game, but is now a business is damaged in the eyes of all, including the many youngsters who regarded three of you as heroes and would have given their eye teeth to play at the levels and with the skill that you had."