LONDON, Sept 26 Pakistan test captain Salman Butt and his opening bowlers Mohammad Amir and Mohammad Asif have been suspended under the International Cricket Council's (ICC) anti-corruption code.
The trio, who have said they are innocent, face possible life bans after allegations that they arranged for Amir and Asif to bowl no-balls at a pre-arranged point in the fourth test against England at Lord's, a practice known as spot-fixing.
It is the most serious crisis to hit world cricket since the match-fixing scandal 10 years ago.
WHAT IS SPOT-FIXING?
Deliberately manipulating incidents within a match when one or more players agree to under-perform. For example, a bowler might bowl consecutive wides with the first two deliveries of his second over or a batsman could make sure he does not reach double figures.
Gamblers also bet on "brackets", events within a 10-over spell such as the number of runs a team will score in that period.
The incidents in themselves can seem trivial and may not affect the result of the match. Twenty20 cricket, which has blossomed over the past five years, is seen as particularly vulnerable to spot-fixing.
WHY IS T20 CRICKET SO SUSCEPTIBLE?
Because of its all-action nature, with wickets tumbling and runs scored at breakneck speed, individual incidents are quickly forgotten.
Tim May, the chief executive of the international players' union FICA, is one of several influential figures in the game who believes that the sheer number of Twenty20 matches now being played could tempt players to take money from bookmakers in return for spot fixing.
Betting on cricket matches from around the world televised in India is a hugely lucrative business. Gamblers or bookmakers can cash in if they know in advance what a particular bowler or batsman is going to do. Bets are placed on every delivery in a 50- or 20-overs match and players can accept bribes to fix incidents.
Only betting on horse racing at trackside is allowed in India but in practice around half of a market worth billions of dollars is estimated to be illegal betting, mostly on cricket. Although betting is illegal in Pakistan, a Muslim country, it is a thriving underworld industry in Karachi and Lahore.
WHAT EVIDENCE IS THERE OF SYSTEMATIC SPOT-FIXING?
Rumours have abounded since the advent of the Indian Premier League (IPL) T20 tournament two years ago although nobody has ever been charged. During last year's Ashes tour of England an Australian player reported that he had been approached by a suspected illegal bookmaker in the team's London hotel.
Former Pakistan captain Rashid Latif told Reuters he believed matches in the now defunct Indian Cricket League, also a T20 tournament, had been fixed.
WHAT WAS THE MATCH-FIXING SCANDAL?
Three international captains Hansie Cronje (South Africa), Salim Malik (Pakistan) and Mohammed Azharuddin (India) were banned for life in 2000 for helping to influence the results of matches.
Match-fixing had become established in one-day cricket in the 1990s and suspicion centred, in particular, on the one-day tournaments staged at Sharjah in the United Arab Emirates.
As a result the ICC founded its Anti-Corruption and Security Unit (ACSU) to monitor all international matches. The ACSU monitored the third IPL tournament in India this year but not the second in South Africa last year because the Indian board thought the fee charged by the ICC was too high.
(Compiled by John Mehaffey; Editing by Clare Fallon; To query or comment on this story email email@example.com)