BT's free spam filter, launched earlier this year to crack down on nuisance calls, has identified accident claims as the worst offender for nuisance calls with 12 million made in the first week of March.
Some two million customers have signed up to the BT Call Protect service, which it says has diverted 65 per cent of calls to the junk voicemail box.
Accident claims made up 41 per cent of nuisance callers; followed by scammers fishing for personal details (18.5 per cent); computer scams (12.6 per cent); debt collection (7.5 per cent) and PPI (6.4 per cent).
It was recently revealed that hundreds of staff were hired by scammers in Indian call centres to defraud TalkTalk customers.
BT said the service harnesses huge computing power to analyse large amounts of live data.
Rogue numbers are identified and added to the BT blacklist, which proactively diverts nuisance calls before they reach customers, unlike reactive blocking where the calls reach the customer and the numbers are changed frequently to avoid detection.
BT said customers are making more than 80,000 calls a week to BT Call Protect's 1572 number to add numbers to their personal blacklist.
BT estimates that if all its customers signed up to BT Call Protect, it could divert 1.6 billion nuisance calls a year. It is thought that PPI and accident claims companies alone are responsible for 800 million of these calls. ®