Campaigners are calling on Southampton to honour thousands of D-Day heroes by saving a rotting relic of the famous landings.

The Grade II-listed structure is alongside the Red Funnel terminal, close to the spot where a huge number of troops embarked on the liberation of Europe in 1944.

Temporary roadways known as Whales linked the floating Mulberry harbours to the Normandy shoreline, enabling soldiers, supplies, and vehicles to be offloaded.

The Southampton Whale is partly submerged and is said to be in a poor state of repair.

Now, makeshift banners highlighting the importance of D-Day have been unfurled nearby as Southampton prepares to mark the 80th anniversary of the landings, which led to the end of the Second World War.

Daily Echo: Whales linked the floating Mulberry harbours to the Normandy shoreline, enabling soldiers and supplies to be offloadedWhales linked the floating Mulberry harbours to the Normandy shoreline, enabling soldiers and supplies to be offloaded (Image: Supplied)

In a separate development, Southampton historian Kingsley Miller is urging the Marchwood-based 17 Port and Maritime Regiment to pull out of a D-Day parade on June 6.

In an open letter to the commanding officer, he claims the regiment is involved in a secret project to "remove" the Whale.

He adds: "I would urge you not to exercise your right to march through the city until you have an undertaking that the structure will be placed in Mayflower Park overlooking the water."

READ MORE: How Southampton is planning to commemorate the 80th anniversary of D-Day on June 6

But an army spokesman said the regiment was not linked to any plan to remove the structure.

He added: "The regiment will exercise their Freedom of the City as planned. The commemorations are an opportunity for our personnel to show their connection to the community and to honour the sacrifices of those who took part in the operation."

Daily Echo: Sections of the Mulberry harbour at Southampton docks. Sections of the Mulberry harbour at Southampton docks. (Image: Supplied)

Mr Miller has also sought the support of Royston Smith, Conservative MP for Southampton Itchen.

Mr Smith said: "We are fortunate to retain the Whale section of a Mulberry harbour in the city as a reminder of this incredible feat of engineering and as a link to the millions of troops who passed through Southampton to liberate Europe.

"I hope the city council and other interested parties are able to secure a future for the Whale and bring greater awareness to the city’s role in D-Day."

READ MORE: D-Day veteran returns to the New Forest beach from where he embarked on the liberation of Europe

The council does not own the Whale but confirmed it was a Grade II-listed structure.

Council leader Lorna Fielker said: "Any proposals around its long-term preservation that would affect its special architectural and historic interest would require Listed Building Consent and would be discussed with Historic England.

"The council recognises the importance of D-Day to the city and has developed a programme that is proportionate to its available resources with other partners."

Historic England said it was not clear if the Whale went to Normandy or was held in reserve as a spare.