The mail piece resembles a torn out newspaper page, with a memo attached reading 'thought this might help you' from one of NatWest's new business managers.
TBWA/GGT is behind the activity which is described by account director Alex Ainslie as the most detailed campaign it has done in this sector.
"Not only is the creative very distinctive it is also subtly different according to which banks prospects have accounts with," said Ainslie.
To HSBC bankers, the 'Dear Sandra' letter-writer bemoans how he can never get through to his bank manager with Sandra suggesting cal-ling a NatWest response number. For Lloyds TSB bankers, it complains of extra charges while trying to form a relationship.
After the mailer is sent, prospects receive a call from NatWest's own internal call centre to qualify if they are a hot or cold target. Hot leads are then forwarded to actual NatWest managers.
More than 100,000 mailings have been sent, with an ongoing programme continuing until autumn. According to Ainslie, the creative is already outperforming a more functional, offer-based test mailer.