In 1997 a project was initiated to improve the 'read' quality of the Optical Character Recognition (OCR) of postcodes in the addresses. Following initial trials in late 2001 the new technology was trialled in production in Greenford in 2002 and then rolled out nationwide.
Mail items processed using AI technology were identified with an "A" prefix in the Letter Quality Mark (info coming soon on a blog near you !) or in the address/date block.
The "A" prefix was dropped in 2008 at the same time as the implementation of PostJet printers.
In 2001, along with the introduction of Royal Mail’s Address Interpretation (AI) system, video images from all Mail Centres of mail items with unreadable addresses are fed to one of four special handling centres for manual coding. The four Manual Data Entry Centres (MDECs) are based at Doxford (Sunderland), Plymouth, Stockport and Stoke, and were each equipped with about 400 workstations, though with improved technology the staff at the MDECs has been reducing.