Peter Bleach, who ran his business from his former home near Ravenscar, has always maintained his innocence and says he should never have been jailed.

He spent eight years in jail for alleged gun running although, under Indian law, he could have received the death sentence.

He claimed to have been held at gunpoint by terrorists and forced to parachute weapons into Western Bengal.

He has also maintained he deliberately botched the operation to ensure the weapons were found by police.

Mr Bleach, who contracted TB in jail, was freed four years ago following a campaign to release him from his life sentence after it was discovered that the authorities in Britain had been tipped off about the incident.

Now, he can be found working at Helmsley Castle, which dates back nearly 800 years.

He said: “The castle is a wonderful place to look around and it gives me great pleasure to explain the history of it.

“One of the great things about spending time in a foreign jail is you appreciate home a lot more and this is as far as you can get from a jail cell in Calcutta,” he added.