Britannia 4-6-2 No 70020 Mercury, from Oak Oak Common shed, after arrival at Bristol Temple Meads with the down 'Merchant Venturer' shortly after the train commenced in summer 1951.

Peter Kerslake says "70021 will come off its train to be turned and made ready at Bath Road for its booked return duty, the 4.15 p.m 'Bristolian' back to Paddington. The 'Merchant Venturer' ran from the opening day of the Festival of Britain, 3rd May 1951, and lasted for ten years until 9th September, 1961, whilst 70021 remained at Old Oak until moving to Cardiff Canton in December 1956."

Photo: J.D. Mills/Rail Archive Stephenson