A team from the Guinness Book of Records visited him at home with owner Tracy Westwood and measured his purring at 67.8 decibels, which is almost as loud as a shower or a dishwasher.
Ms Westwood, from Torquay, UK, said: “Occasionally when he’s really loud I have to repeat myself. When you’re watching films you have to turn the telly up or put him out of the room, if he’s eating he’ll purr loudly. I can hear him when I’m drying my hair.
“If he’s cleaning he gets louder and if the telephone rings I do get people asking me ’what’s that noise in the background?’ I tell them it’s the cat but I don’t know if they believe me.”
Ms Westwood found Merlin at a rescue centre.