Mr Marjoram, 46, of Kettering, followed in the footsteps of his boyhood hero Arnold Schwarzenegger to claim the world championship crown in the under-65kg class, in Italy, on Saturday.

Mr Marjoram, who is a personal trainer at Bodyshapers Gym in Kettering, said: "Never in a million years would I have dreamed I could win Mr Universe.

"When I first started training I just wanted to get good enough to enter a local show.

"The thought of winning Mr Universe would have been laughable."

When he started training in his bedroom with rusty, secondhand dumbbells at the age of 19, Mr Marjoram was 5ft 3in and 8st 4lb.

He said: "When I started training I was quite a small fellow, five foot nothing.

"I wanted to build myself up. I wanted not to be small, so I went to the gym."

Mr Marjoram, who lives in Hill Street, was so shy he waited three years before joining a gym – but he is glad he did.

He said: "It has been great. It has completely changed my life.

"It gives you confidence. It's a reason to get up every day."

But it has not been easy.

Mr Marjoram gets up at 3.30am every day to train, before taking clients from 8am, and has to watch everything he eats.

The competition in Campobasso, Italy, was the first time Mr Marjoram had competed in such a lightweight category.

In the days leading up to the weigh-in he was on a no-carbohydrate diet of turkey breast and protein shakes and could only have sips of water in case he gained weight.

As soon as he had qualified he went straight to his hotel room and gorged himself – on dry, uncooked oats. He treated himself to pasta, salmon and gateau later that evening and had put on 10lb by the following day.

Most bodybuilders reach their prime in their early 30s and Mr Marjoram was by far the oldest in his category, but he said the time it has taken him makes him appreciate it more.

He said: "It has made me a much better person.

"Some people are born runners, some people are born weightlifters. I wasn't.

"I had to work hard."