Seventy-stone man moved to hospital for treatment
It is understood Mr Mason will undergo gastric bypass surgery at St Richard's Hospital in Chichester and it is thought he was transported on Wednesday in a specially built bariatric ambulance designed for obese patients.
A spokesman for East of England Ambulance Service said: "While our ambulances can deal with the majority of the population we serve, we sometimes need to call on partner services which provide vehicles to move patients who exceed 25 to 30 stone.
"St John Ambulance is one of the companies which we work in partnership with for this specialist service.
"We cannot comment on individual cases but we take all the necessary steps to ensure each patient is conveyed in an appropriate, safe, dignified and professional manner."