If Sheppey’s bomb ship the Richard Montgomery blows up, the shock of the explosion could be felt more than 5,000 miles away.

That is one of the fears revealed in a new documentary made by Sittingbourne director Ken Rowles.

Half a dozen interested parties, including Tim Bell and Stan Hampshire of the Isle of Sheppey Sailing Club and former Sittingbourne councillor Simon Clark, have been given a sneak preview of the 50-minute film.

The documentary, A Disaster Waiting To Happen, has cost more than £100,000 to make but is now gathering dust at the BBC while executives discuss whether to show it or not.

Mr Rowles, 72, admitted: “It is very frustrating. My investors now want their money back. I am hoping other broadcasters will take up the opportunity to show this important film.”

The Montgomery, an American Liberty ship built to carry essential supplies across the Atlantic to Britain during the Second World War, sank off Sheerness on August 20, 1944, with 1,400 tonnes of explosives on board.

The film includes new footage shot on the Montgomery’s sister ship, the Jeremiah O’Brien in San Francisco, one of two Liberty ships now turned into floating museums.

It shows vividly how massive the Montgomery was before she broke her back and sank.

There is a revealing interview with Captain Mike Fagg from the Folkestone Salvage Company, which blew up a smaller boat, the Polish-built Kielce. The ship was also loaded with Second World War munitions.

That explosion, 50 years ago this month in the English Channel on July 22, 1967, sent shock waves that could be felt 5,000 miles away. The bang also caused a 2ft tidal wave, which flooded Folkestone and caused hundreds of thousands of pounds of damage.

Mr Fagg recalled: “We had done operations like this before and were expecting a small ripple and some spray. Instead, we had a huge plume of water and phosphorous bombs raining down on us.”

In the film, MP Gordon Henderson says no government would now sanction evacuating 44,000 people from Sheppey for weeks or months while experts removed the remaining bombs from the wreck.

For the first time, the documentary logs in public the lengths the Montgomery’s skipper, Capt Charles Wilkie, went through to try to ensure his ship was given a safe berth.

He even came ashore and stayed at the Jolly Sailor pub in Blue Town to collect up-to-date charts. But his pleas were overruled by the Ministry of Defence.

As a storm raged, the Montgomery crashed on to the sandbank and cracked in half, letting its lethal cargo spill on to the seabed.

Some say the documentary, presented by broadcaster David Riley with commentary by Lovejoy actor Ian McShane, should be shown to all Swale schoolchildren.

Others believe it will only encourage terrorists to launch a devastating attack.

Mr Rowles’ company, Action Plus Media, is trying to raise further cash through the crowd-funding website Indiegogo.