Police have confirmed six more people have been arrested as part of a probe into the alleged fixing of horse races.
The two women and four men are among 22 people now on bail until April 2005 on suspicion of conspiracy to defraud.
In September, champion jockey Kieren Fallon was one of 16 people arrested, including two other jockeys and a racehorse trainer, in dawn raids.
Officers, who are checking over 1,000 items, including several computers and 59 phones, expect to make more arrests.
Detective Chief Superintendent Steve Wilmott, leading the operation for the
City of London Police, said: "We have made a large number of arrests, and we
expect to carry out more over the next few months.
"This has grown into a huge investigation and will require more time and resources to fully investigate. For this reason we have taken the decision to extend their bail to early next year."
Police confirmed that one woman was arrested in Shrewsbury, another in Sheffield, one man in Doncaster, two men in North Yorkshire and another man in Bristol.
None of the six arrested, who were held at various times since the original swoops, are jockeys or trainers.
The inquiry began with more than 130 officers raiding 19 addresses across Suffolk, North Yorkshire, South Yorkshire and Hertfordshire on 1 September.
Allegations of fixing involving more than 80 races over the last two years are being examined.