An underwater mission to discover the remains of a missing plane which vanished more than four decades ago has made ‘significant progress’ following a bright summer.

In the latest hunt for the plane, Grahame Knott and the Deeper Dorset team have been out almost every day in July and August to search for the wreckage of a US Air Force Hercules transporter plane that went missing from radar somewhere over the English Channel in May 1969, around 40 miles south of Portland Bill.

The USAF plane was taken by Sergeant Paul A. Mayer from his base in Suffolk, apparently with the intention of flying home to his family in the US.

However, the plane disappeared somewhere over the English channel and consequently, the fate of the plane and pilot remain unclear - a mystery that Mr Knott and his team were hoping to clear up before the end of the summer. In one of the latest trips out, the team found an old iron ship from the age of sail, which Grahame said probably dates from the mid-19th Century.

He added: “We are confident it has never been dived but its remains are slowly being eroded by current and trawl fishing damage.

“The dark band crossing from left to right shows us the outline of the hull against the lighter background of a seabed of shell and gravel.”

The team have also been reviewing the UK Hydrographic Office records which collect data about the seabed and coastline, primarily as a guide and benefit to mariners and the Royal Navy.

They also reveal the location of all known wrecks as well as other potential hazards or snags they find during surveying, known as ‘marks’.

Following a long review of their records, one mark has caught the team’s eye

Grahame said: I’ve never seen a mark listed like this before. It’s within our search area but is listed as a low-lying unknown mark and thus graded geological or a natural feature but it’s worth taking a closer look.”

The group is also raising money to help fund the project by selling limited addition photos by Aviation artist Simon Cattlin which depicts Paul Meyer having flying just off the South Coast.

Alongside this, two people have also come forward with useful information which could help to narrow down the search area.

Grahame added that the discovery and information was a step in the right direction but he stressed that the team could be at it for weeks or even months.

He added: “We took advantage of the weather and made several trips out however we’re just going to keep cracking on to finding the remains of the plane.

“He hope to find something like the propellers which would allow air accident investigators to determine why and how the plane crashed, however, we are leaving no stone unturned and the search goes on.”