My notebooks have let me down on this one. It was taken at Wigston South Junction, a few miles south of Leicester, on the afternoon of 7 February 1981 and shows a Class 45 diesel passing the signal box with an express bound for St Pancras. The light angle would suggest it was taken around 16:00 and the loco was probably one of 45.117/121/128/132/142/143/144, all recorded as seen that day.