You may have seen Bus Inspectors using PDAs to check addresses and
issue penalty fares. They use what looks like an XDA II. The Rapid
project was to create a very similar system for use by Tube RIs*. They
did not have to work underground, as such, they would send PFN
information telephonically once above ground. Electoral roll info was
to be stored on the device itself. The project was in development for
about two years but the company which had been asked to develop the
system produced nothing physical and the project was abandoned.


*The observant among you may notice that the latest name badges for
RCIs give their job as "Revenue Inspectors".