I went down to the Crich show in Snowdrop when the clutch went on the M1. It was the same as a slipping clutch but it happened suddenly. I rang the breakdown service and when they got be back I jumped in Project Blue (taking Anita with me) getting to Crich 3 hours later than planned. It turned out to be a great day and we went back the scenic route going up the A6. Sure beats the M1!
I'm still puzzled as to why my poblem occurred. I suspect a worn clutch plate but as I've been typing this I'm wondering if a broken half shaft in the rear axle could be the problem. I can eliminate that one easily enough. For now Snowdrop is out of action until I can solve the problem.