A holidaymaker has lost his claim against British Airways after saying he was injured by being forced to sit next to an obese man who was “the size of Jonah Lomu”.

Stephen Prosser, 51, had claimed he suffered personal injury and loss of earnings after being made to sit next to the large passenger during a 12-hour flight from Bangkok to Heathrow.

But, on Thursday, his civil claim against the airline at Pontypridd county court was dismissed by the district judge, Andrew Barcello, who said Prosser had exaggerated the description of the other passenger.

The judge said that, while Prosser may have exacerbated a degenerative spinal condition during the flight, he could have just asked to swap seats with another passenger.

Barcello said: “He is articulate, intelligent and forthright. He need only have explained to fellow passengers that he was finding the flight uncomfortable, rather than knowingly subject himself to an injurious event.

“In my view, his statements were intended to increase the size of the claimed encroachment and to create an exaggerated picture, rather than a genuine account.

“I accept that the passenger in seat 37J was a large man, both in the sense that he was very tall, broad, and carried significant body weight. It is likely that there were occasions when, as a result of his size or his movements within his chair, that he did cause an inconvenience to Mr Prosser.

“But I do not accept the suggestion that his size was such that Mr Prosser was compelled to sit in an awkward way for the duration of the flight by virtue of him encroaching upon his seating area.”

The judge added that Prosser had “unrealistic” expectations of how much room he should have had “given the class of cabin he chose”.

Prosser, a self-employed civil engineer, had told the court earlier this month that he chose not to leave his seat because doing so would “hassle” the other passenger getting up, and did not take issue with him because he seemed “self-conscious”.

Prosser described the man as being 6ft 4in (193cm) and weighing approximately 22 stone (140kg), and claimed he reminded him of the late New Zealand rugby union player Jonah Lomu.

Prosser, who is 5ft 3in, said: “He was that large that he had to force his buttocks between the armrests of the seats.

“He sat with his knees wedged against the seat in front and the rest of his body was overspilling into my seat by some inches.

Prosser, from Tonypandy, south Wales, said the incident in January 2016 left him with a continual back spasm and an injury causing the sacroiliac joint at the bottom of his spine to dysfunction.

He said he had been unable to work overtime for three months as a result of his back pain, and it had left him lacking energy, which had affected his relationship with his partner and forced him to give up mountain biking.

Jack Harding, representing Prosser, said a figure of £4,100 had been submitted for the loss of earnings claim.

Chris McLindon, the customer service manager on the flight, said in a witness statement that Prosser did not seem to be in any discomfort and “at times he was asleep”.

Following the verdict, a spokesman for British Airways said: “We are pleased that the court agreed that Mr Prosser had room to fly comfortably.

“Our cabin crew will always do their best to make sure all our customers have a smooth journey, and in this case provided extra pillows and blankets to help Mr Prosser sleep.”