You wouldn't get ANY remotely sharp tools onto a plane in the UK. You can't even carry liquids above a certain volume into the cabin. Nail files, tiny scissors, screwdrivers are a complete no no here in the cabin baggage, as well as a quite severe size limit on the bag - oh yes, it's one bag too.
I think the paranoia about cabin baggage is largely there to stoke up fear of terrorism just so we keep quiet about our civil liberties being eroded.