After the disastrous accident at Clapham in 1988 the Hidden enquiry's recommendation No 46 obliged the BRB to install Automatic Train Protection (ATP) on a large percentage of its passenger lines within five years, after selecting which ATP system would be used. 
In January 1990 I became involved with the track testing phase of the introduction of the ATP Pilot Schemes on BR both on the WR main line (GWML) and the Chiltern Lines (CL). This phase was to last 'about six weeks'. In the event I was involved with ATP for over 7 years!