Highway Insurance will be introducing a monitoring system to check stress levels in a claimant's voice to fight fraud, said Highway's general manager Stuart Davies.

The system, which has yet to be installed by Highway but is used by Churchill and Direct Line, allows insurers to gauge whether a claimant is lying or exaggerating the extent of the claim.

However, Davies denied this amounted to making claimants take a lie detector test. "It is not a lie detector. It is a way of fast-tracking people and processing claims faster. If a person fails the test, then we just process the claim in the normal way."

Only claimants who ring the company's call centre helpline would be monitored and Highway would not cold-call claimants indiscrimately to try and catch them off guard, he said.

The Insurance Ombudsman's spokeswoman Iris Baker said: "We would accept its findings as one piece of evidence. However, we would not rely on it being conclusive in a case."

She added: "You have to take into account the stress of the situation. Someone could have written down all the details and then speaks them down the phone, which is not a normal speech pattern.

The Association of British Insurers (ABI) backs the system.