Solenoid on the starter motor has gone, probably easiest to replace the whole unit. They are available through EuroCarParts from £48.03 (not sure if it includes VAT!) It should be easy enough to fit, probably 1 hrs. labour at the most.
http://www.eurocarparts.com/ecp/c/Vauxhall_Corsa_1.2_1996/p/Car-Parts/Electrical-and-Lighting/Electrical/Starter-Motors
Oh by the way, no such thing as a 1.1l in 1996, so i guessed it was the 1.2.