Cunard is set to turn its back on Southampton in favour of Liverpool to celebrate the 175th anniversary of the world-famous shipping line’s foundation.

It comes at a time when the two ports are locked in Cruise Wars over the northern port’s attempt to use public funds to muscle in on the British cruise industry, which has its northern European hub in Southampton.

A major campaign, co-ordinated by the UK Cruise Ports Alliance, backed by Southampton, together with other UK ports, is now under way to stop Liverpool’s plan’s to become a “turnaround’’ port.

On Thursday a petition, with more than 10,000 signatures, is to be handed into 10 Downing Street demanding the Government does not to allow Liverpool to berth cruise ships in between separate voyages, unless the city pays back more than £20m of public funding it was originally given to build the present passenger terminal.

Ironically, on the same day, Cunard’s flagship, Queen Mary 2, is due to arrive in Liverpool for a brief visit during a round-Britain cruise.

Meanwhile, Liverpool is confident the shipping line will mark the major milestone in the company’s history by sailing its flagship, Queen Mary 2, together with Queen Victoria and Queen Elizabeth, up the Mersey on the same day, July 4, 2015.

Cunard denies it has any intention of snubbing Southampton and stressed “no decision’’ has yet been made to hold the event in Liverpool as it has “not yet explored all the practicalities”.

However, politicians in Liverpool seem to have no doubts the 2015 anniversary will take place in the city, with Eddie Clein, deputy chairman for the city’s leisure, tourism, and culture saying: “This is a huge accolade. Cunard clearly recognises the efforts Liverpool is making to up its game in the cruise market.’’ Another Liverpool councillor, Barbara Mace, said; “This is a wonderful coup for Liverpool. Many thanks to Cunard for sharing its 175 years.’’ A Cunard spokesman said: “No such decision has been made and we have not yet explored all the practicalities.

“But Cunard started in Liverpool and it seems entirely appropriate that our 175th anniversary event should happen in the place from where our first ship set sail on July 4, 1840.

“This is not a snub to Southampton, it is a logical aspiration.

You would not celebrate the departure of the Pilgrim Fathers in Aberdeen, would you?

“It is common sense to celebrate such events where they happened.”

Last week the Cunard vessel, Queen Elizabeth, arrived in Liverpool for the first time, while QM2’s presence is part of the six-day long, Mersey River Festival.

If Liverpool is confirmed as the venue for the anniversary event, all three of Cunard’s ships will be present in the Mersey on July 4, 2015, exactly 175 years to the day when Samuel Cunard inaugurated the company’s transatlantic service with the 1,154-ton Britannia, from Liverpool to Boston.

Last week, Cunard president and managing director Peter Shanks, speaking as Queen Elizabeth arrived in Liverpool, described the northern port as the company’s “spiritual home’’.

He also told the Daily Echo that there was no chance of Cunard or any of its ships moving home to Merseyside.

Southampton people will not have to wait until 2015 to see Cunard’s trio of Queen ships together, as the fleet will be alongside Southampton Docks on June 5, next year.

The Royal rendezvous – part of the Queen’s Diamond Jubilee – will mark the company’s long association with the monarch, whose most recent contact was the naming of Cunard’s latest ship, Queen Elizabeth, in the port last autumn.