The system, which uses barcode technology to track and monitor letters through to delivery, is claimed to be the first service of its kind in the UK to fulfil high volumes and could be used by direct mailing businesses to analyse customer responses to mail shots.

The venture, which has been undertaken by the mailing giant in partnership with St Ives and software developer PrintSoft, is said to help customers "evaluate and improve the performance of their mailings".

St Ives supported the development and testing of the service, including a 2m customer mailing run.

John Charnock, technical director at St Ives, expects the service to appeal to users such as marketers that are able to analyse the time cycles of their mailing campaigns.

He said: "Red Tag is a way to track mail while also showing up non-deliveries through wrongly-addressed mail. It opens up a dialogue with the customer." 

In 2007, Royal Mail appointed St Ives to supply its print management services in a deal worth £40m-a-year.

Charnock said using PrintSoft as its technology partner has allowed it "to target the widest possible market of potential users".

The specialist developed the automation software, Workflow-Q, that underpins the system including the barcoding and tracking technology.

Chris Buckle, sales manager at PrintSoft, said: "Using the system really offers a value-add for direct mail companies using the service to analyse the effectiveness of their marketing."

Every item sent using the service is scanned by Royal Mail's sorting machines in each of its 69 UK centres prior to delivery to its recipient.

Colin Bradshaw, head of data strategy at Royal Mail, said: "The objective of the new service is to help customers evaluate and improve the performance of their mailings by monitoring delivery and identifying customer responses."