hi guys, just jumped in my car, (declutched and put in 1st ready to go as not to wake neighbours if that makes sense) however car jumped forward when trying to start. slapped myself around the face, tried it again and did the same! pulled it out of 1st and seems clutch isn't working

checked fluid level which was fine, clutch pedal has plenty of feel, springing back and forth quite nicely, but won't go into gear when engine is started

anyone share some light? car has is a mk5 fiesta zetec-s, clutch wasn't slipping at all before, and didnt crunch into gear, really has left me stumped and f***ed off! any advice gratefully taken guys