A harbour that was destined for a key role on D-Day, but which accidentally sank in the Thames Estuary just one mile off Southend on sea, Essex, could in an strange 'twist of fate' protect the area from the risk posed by another wartime wreck situated close by.

WW2 American Liberty ship SS Richard Montgomery sank at the mouth of the Thames 1.5 miles north of Sheerness in Kent in 1944 - with 1400 tonnes of explosives still onboard - the masts of which can be seen near the center of the video.

Experts fear if the Montgomery were to ever explode it could produce a tidal wave of around 5 metres (16 feet) or higher, as well as the predicted blast reaching up to 3 kilometres into the air.

However, as can be seen in this footage at low tide (February 8), the Mulberry Harbour off Southend (the dark block near the top of the video) could potentially provide protection from any tidal wave for a small section of Southend's coastline, reducing and deflecting the impact of the wave energy.

The three masts of the SS Richard Montgomery will be removed this Summer to reduce the likelihood of them triggering an explosion should they collapse onto the hull.