The DCPCU, City of London Police and West Yorkshire Police found around 100 fake and stolen chequebooks along with "professional" printing equipment and materials used to forge cheques at 22 addresses in Leeds, Wakefield, Edinburgh, Glasgow and Hamilton in South Lanarkshire.
Each chequebook contained up to 50 cheques with the potential to forge up to £5m, but detectives believe that the crime ring could have been making £50,000 a week using the counterfeit cheques, and up to £10m overall.
Two women and five men aged between 29 and 33 were arrested on suspicion of conspiracy to defraud last Wednesday and Thursday (17 and 18 October). They were questioned at West Yorkshire police stations and later released on bail.
The DCPCU said that a lack of public familiarity with cheque security and the ease of access to high quality printers, papers and ink via internet buying was creating an "increasingly fertile ground for fraudsters".
DCI Dave Carter, head of DCPCU, claimed that a decline in counterfeit cheque fraud had "ironically left a chink in the door".
Financial Fraud Action UK figures showed that the prevalence of fraudulent cheques rose between 2010 and 2011 despite a decline in cheque usage. However, 90% of fraudulent cheques are detected in the clearing process.
