At the Old Bailey, Westfield pleaded guilty to taking money to intentionally concede runs.
London: The corruption-scarred image of cricket took another hit Thursday when the first English player admitted to fixing part of a match.
The England and Wales Cricket Board responded to Mervyn Westfield's guilty plea by giving players and officials until April 30 "to report approaches or information related to corrupt activities" without the threat of sanction for previously staying silent.
At the Old Bailey, England's highest criminal court, Westfield pleaded guilty to taking money to intentionally concede runs during a 40 overs county match broadcast live internationally.
With his reputation stained after being released by county team Essex, the 23-year-old fast bowler could now join three Pakistan players in being jailed by an English court for corrupting a sport embodied by a spirit of fair play.
As with the case of Salman Butt, Mohammad Asif and Mohammad Amir, Westfield's case hinged on a bowler intentionally performing badly.
But while the Pakistani trio were prosecuted for fixing part of a Test match against England following a newspaper investigation, Westfield was investigated after a tip-off from within the Essex team about the Pro 40 match against Durham in September 2009.
"This was a ground breaking case for Essex police, which was highly complex," detective sergeant Paul Lopez said.
"We are pleased that Mervyn Westfield, a young professional cricketer, has now admitted the charge and we hope that this sends a strong message to professional sportsmen and women around the country — if they intend to get involved in spot-fixing, or think that match-fixing is not a crime, then they need to think again."
The ECB hopes the verdict will encourage other people to come forward with evidence of corruption.
"Information is critical in addressing the threat posed by corruption in sport," ECB information manager Chris Watts said.
"The decision of the board to provide a window for retrospective reporting of alleged approaches will greatly assist ... in compiling a more complete picture of the source and focus of approaches which may have taken place in the past.
"Individuals may not have thought these approaches were worthy of reporting at the time and prior to the decision of the board may have been concerned that the fact that they did not report such activity may have put them at risk of disciplinary action."
Westfield pleaded guilty to accepting or obtaining a corrupt payment at the start of his trial, although his legal team disputed how far the scam was carried out.
While admitting to accepting money to carry out the act, which the judge said amounted to 6,000 pounds ($9,200), Westfield denied bowling in a way that would allow the scoring of runs.
"It is difficult to accept the defendant received many thousands of pounds if he didn't carry out his part of the bargain," judge Anthony Morris said.
"If you agree to concede 12 runs in your first over in exchange for 6,000 pounds and you concede 10 runs in that over, one view of the matter is that even though you were trying to concede 12 runs you would still be guilty because you ... accepted a corrupt payment," Morris added.
It is not known if anyone profited from Westfield's actions.
Sentencing was set for Feb. 10, with Westfield warned he could face a jail term before being allowed to remain out on bail.
The name of another person involved in the case could also be disclosed at that time. The judge said it is a well-known person.
British prosecutors were assisted by the International Cricket Council, which was urged this week to use undercover investigations to identify corrupt cricketers.
It was one of 10 recommendations to fight match-fixing made by the Marylebone Cricket Club, which is viewed as the traditional guardian of the game.
England's Professional Cricketers' Association said the conviction of Westfield should send out a signal that "sport needs to be treated with respect and played properly."
The case highlights that not only international matches are susceptible to corruption.
"Domestic cricket is also a risk because some games are televised on the Indian subcontinent so I suppose those specific matches are the ones we need to worry about," PCA chief executive Angus Porter said.
But the ICC has no authority over domestic competitions.
"The more we tighten up around international events and fixtures, the greater the potential risk ... that these criminal people will focus elsewhere," Ronnie Flanagan, chairman of the ICC's anti-corruption and security unit, said last year. "I think we must be guarded against that."
The trial of the Pakistan players ended in November with the judge warning that cricket fans might never be able to trust the outcome of matches again.
The scam that jolted the authorities into launching its most widespread corruption investigation came in the middle of Pakistan's Test against England at Lord's in August 2010 but was only uncovered by investigators from the now-defunct News of the World tabloid.
Butt, the former captain, was jailed for 2½ years, Asif for 1½ years and Amir for six months after they ensured no-balls were bowled at specific times.