£27? Maybe not.
In a group, a friend punctured but (presta) they'd screwed the collar on tight and maybe a while ago. So at the side of the road even the strongest fingers could not get it off (to remove and replace the tube). Solution was (as above): pull all of the tube out you could, inflate to discover puncture site, check cause inside tyre and remove, clean sand and apply an 'instant' patch, reinsert-refit-reinflate-ride on.