He is three years old and has dribbled in the past and was seen by a vet - about a year ago then in Jan when he had his vaccinations.
His dribbling was much worse then and she said his gums were slightly inflamed but nothing to worry about. I did wonder if it is stress related because we have a lot of cats that come into the garden and although we do have a microchipped cat flap he is very watchful when he eats.
I am reassured about the stronghold though, thanks.
I will ring the vets tomorrow to get him seen - they were closed today for staff training.