Four jockeys have been found guilty of breaching of the rules of racing following a corruption investigation and handed bans ranging from six months to 12 years, the British Horseracing Authority (BHA) said on Wednesday.

Paul Doe and Greg Fairley were found guilty of the most serious breach of deliberately ensuring horses did not run on their merits and received 12-year bans.

Kirsty Milczarek and Jimmy Quinn were found to have committed corrupt or fraudulent practices with the former also guilty of passing on information for reward. Milczarek has been banned for two years and Quinn for six months.

The quartet have seven days in which to appeal.

Former rider Paul Fitzsimons, now a licensed trainer, was cleared of all charges.

We take no pleasure in uncovering such serious breaches of the Rules of Racing, BHA director Paul Scotney said in a statement.

In the BHA's history, the scale and complexity of this case is unprecedented.

The four jockeys were among 11 people, including two owners, to have been found guilty of charges relating to 10 races between January 17, 2009 and August 15, 2009.

While it is the names of the jockeys that the racing public will recognise, people should be under no illusion that it is the lesser known names who were the instigators of these serious breaches of the rules, Scotney said.

What lies at the heart of this investigation are the actions of two individuals, Maurice Sines and James Crickmore, who, together with their associates, were prepared to corrupt jockeys and to cheat at betting by the misuse of 'inside information'.

The investigation uncovered a network through which Sines and Crickmore engaged in betting activity, in particular with two riders, Paul Doe and Greg Fairley, that impacted on seven of the 10 races in question.

Sines and Crickmore were disqualified for 14 years.

Scotney hoped the penalties imposed would act as a strong deterrent to others for the future.

The case underlines that there is no room for complacency on the part of BHA and others involved with the regulation of sport, he said.

The threat from those seeking to gain an advantage at betting through the misuse of inside information is ever present and this case illustrates that ongoing threat. At its worst this leads to the manipulation of the outcome of races.

The livelihoods of those who work in the racing industry are at stake if they allow themselves to be corrupted by individuals.

(Writing by Sonia Oxley; Editing by Justin Palmer)