Hi John, that symbol is the engine managment warning light, it means the engine ECU has detected a fault and it sounds like it has gone into "limp home" mode where it limits the engine to prevent serious damage!! you will have to get it connected up to a diagnostic code reader to find the fault, most good independant garages and tyre & exhaust places have the kit to do this and charge around £25~30 main dealers you can put a 1 in front of those prices!!
nigel, April 2009