The club have been fined £215,000 by an independent disciplinary panel, of which 50% has been suspended for two years.

Both parties have the right to appeal.

Harlequins director of rugby Dean Richards plus two members of the club's medical team - physiotherapist Steph Brennan and Dr Wendy Chapman - had misconduct complaints dismissed.

But Williams and the club were both found guilty of fabricating a cut to the mouth in order to allow substituted fly-half Nick Evans to return to the field with five minutes remaining.

Television cameras spotted Williams winking towards the bench with 'blood' smeared around his mouth.

Harlequins managed to engineer a late drop-goal attempt for Evans but the New Zealand fly-half was struggling with a knee injury and pulled it wide.

The ERC released a statement tonight which read: "It was the view of the committee that this was a very serious offence and one that damaged the reputation of the tournament and of rugby union, and accordingly the committee imposed a fine of 250,000 euros on Harlequins, of which 50% is suspended for two years.

"The committee also suspended Mr Williams from playing rugby for a period of 12 months up to and including 19, July 2010."

The independent disciplinary committee was chaired by Robert HP Williams (Wales) and also comprised Pat Barriscale (Ireland) and Dr Stuart Reary (Scotland).

The panel reconvened today having previously met on July 2 and 3.

Over the course of the hearing, the committee heard submissions from representatives of ERC and Harlequins and from a number of witnesses as well as considering further evidence, that included broadcast footage from the game.

Harlequins tonight questioned how Williams and the club could be found guilty if Richards and the medical staff were acquitted.

A club statement said: "Harlequins are both surprised and disappointed at today's decision by the ERC disciplinary committee to find Harlequins and Tom Williams guilty of misconduct - particularly so in the light of the acquittal of Dean Richards, Steph Brennan and Dr Wendy Chapman on similar or identical charges.

"The club and the player will consider their position in the light of the written judgement due to be handed down by the disciplinary committee."