Chubb is facing legal action from a former employee claiming a campaign of bullying and sexual harassment, Insurance Times has learned.
David Bonner, who was a claims handler in the insurance giant's personal accident and travel claims division, is seeking damages for an alleged sustained campaign of victimisation and intimidation.
He is understood to have resigned in May 2006.
Chubb strongly denied the claims. Monique van der Linden, UK and Ireland claims manager at Chubb, said: "We can confirm we are dealing with an employment tribunal claim of unfair dismissal which claims sexual harassment and bullying [and] which has been brought by a former employee."
She added: "As part of a formal grievance procedure, we have already undertaken a thorough internal investigation of the matter and found no evidence to support the claim."
A claim for constructive dismissal and breach of contract has been lodged with the Employment Tribunal. Chubb said a formal defence to the claim had been submitted.
A tribunal hearing has been scheduled for 8 January.
Bonner was unavailable for comment.
The claims division at Chubb is believed to have lost a number of staff in the past six months, including three senior people. These are understood to include Ruth Roberts, casualty claims team manager, and senior claims examiners Alison Singers and John Warren.
Warren is thought to have had a payment authority of £1m.
Chubb played down the departures, insisting that staff turnover in the claims division was not high.
Van der Linden said: "Our staff turnover rate [in the claims department] this year is 10% which is well below the insurance industry average of 16%.
"Our 2006 figure is also in line with our 2005 figure for the same period. What may appear to be a large number of resignations is actually not the case."