problem with starter lead for mk 3 1995 golf gti!!!!?

hi, i have a mk 3 golf gti, im having problems removing the lead from the starter to the engine, the lead has perrished and i need to replace it but i cant remove it!!!!!!!, the lead comes from the plug in the starter and goes under the engine, and plugs in underneath, its the plug underneath that im having problems with, how does it come out????????????