Normal service resumes on 28 April.
The latest news reads-
"On Friday 28 April we will restore the normal timetable on the West of England Line.
An amended timetable was put in place on Friday 21 following a problem related to the biofuel used by the diesel trains that operate services in the Basingstoke, Exeter, Romsey, Salisbury and Yeovil areas.
The problem, which is still under investigation, caused fuel filters on a small number of trains’ engines to become blocked, impacting their acceleration and top speed.
Following enhanced maintenance, the use of fresh fuel and a deep clean of our fuel storage facilities, our trains are now performing as expected. Today, Thursday 27, we are operating an hourly service between Exeter St Davids and Basingstoke, with a number of peak services running through to London Waterloo.
Tomorrow, Friday 28, we will operate the usual service in the Basingstoke, Exeter, Romsey, Salisbury and Yeovil areas."