Eight men have been arrested in early morning raids across England as part of an investigation into scam texts claiming to be from Royal Mail.

The men were detained on suspicion of fraud involving “smishing” texts claiming to be from delivery firms.

The operations on Monday in London, Coventry, Birmingham and Colchester took place during a week of action by officers from the Dedicated Card and Payment Crime Unit (DCPCU).

Seven of those arrested have been released under investigation, while one suspect from Enfield, north London, has been charged and remanded in custody ahead of a court appearance in June.

The police said ongoing investigations were expected to result in further arrests and charges.

Royal Mail is just one of the delivery firms used by criminals in messages designed to trick people into giving away details which can be used to commit further frauds.

The texts tell recipients there is an unpaid fee on a parcel and that they need to pay it before redelivery can be arranged. Links direct them to fake websites where they are asked for personal and financial details that can be used later by the fraudsters.

The Guardian has heard from people who followed a link in a text and were later contacted by scammers who tricked them out of thousands of pounds.

The police searches uncovered several devices used in the scams and financial details relating to customers.

DCI Gary Robinson, the DCPCU’s head, said: “The success of these operations shows how through our close collaboration with Royal Mail, the financial services sector, and mobile phone networks, we are cracking down on the criminals ruthlessly targeting the public.

“Ongoing investigations are now under way and we will continue to work together to bring those committing smishing scams to justice.”