Police have arrested 35 people over a multi-million pound cheque book scam.
Cheques were being cashed for up to £1,200
Up to 400 officers carried out raids on Tuesday at 36 addresses across London, Surrey, Kent, Cambridgeshire, West Midlands, West Yorks and Manchester.
Cheques stolen from books sent by banks through the post to people in Golders Green, north London were being cashed for up to £1,200 each.
The Metropolitan Police estimate the thefts have netted the thieves £20m from across the country.
The investigation, codenamed Operation Bangor, began in June 2004 when residents in Golders Green, north London, reported large sums of money disappearing from their bank accounts.
Bogus bank accounts
By August 2004 police in nearby Barnet were receiving on average 12 reports of such crimes every day.
In total, they have received almost 1,200 reports of crime relating to 1,500 missing chequebooks.
Victims were discovering that cheques ranging between £800 to £1,200 were being cashed from chequebooks they had never received from their banks.
Royal Mail Corporate Security helped identify an employee allegedly involved in the theft.
Police said that cheques were being passed to a group of men outside Royal Mail who then fraudulently cashed them.
It is believed up to 200 people would then place the money in a series of legitimate and bogus bank accounts.
The scale of the fraud in Golders Green area is estimated at up to £5m, but cheques have been traced across the UK accounting for an estimated £20m.