BORIS Johnson has been warned his plan to unveil the design for a new British flagship ahead of the Queen’s jubilee will “backfire badly” – and boost the case for Scottish independence.

The Prime Minister is supporting plans to spend an estimated £250 million on a replacement for the Royal Yacht Britannia – despite a dire cost-of-living crisis

The Telegraph reports that the UK Government will reveal details of the design ahead of the Queen’s 70th Jubilee celebrations in spring.

Government officials predict it will be "the jewel in the crown" of the UK Government’s new shipbuilding strategy, stating the vessel will be a “working trade ship” as opposed to a royal yacht.

But SNP MP Tommy Sheppard condemned the proposals and suggested the Prime Minister was displaying the good judgement one would expect of a medieval tyrant.

“I think if it looks like a royal yacht, sounds like a royal yacht, it’s probably is a royal yacht,” he told The National. “And I think obviously the Tory government regards this as an appropriate thing to do during the Queen's Platinum Jubilee.”

But he predicted the announcement will “backfire badly” on Johnson, strengthen the case for a Yes vote and “do great damage to the royal family”.

Sheppard continued: “I'm sure the last thing the royal family would want is to be seen having this degree of public expenditure lavished on them at a time of great austerity and hardship for many millions of people in the UK.

“This type of misplaced priority underlines yet again the need for Scotland to consider becoming a politically independent country and charting its own course.”

He added: “We can all think of better things to spend £250m on. Trying to try to alleviate the absolute misery that many low-income families are facing in the cost of living crisis would be a good place to start.

“This is a sense of priorities that wouldn't be out of place in some sort of medieval feudal society.”

Johnson is publishing the new shipbuilding strategy on Thursday, announcing his commitment to unveiling the design for the new flagship to "showcase cutting-edge British shipbuilding, engineering and technology, particularly clean maritime technologies".

The National: Initial design for the new British flagship Initial design for the new British flagship

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Officials say the new designs will represent a "restatement of the values and business case of the ship". A source assured the Telegraph people will be “hard-pressed” to see anything that “looks like recreational luxury” on the £250m vessel.

The shipbuilding strategy describes it as "a visible demonstration of the UK's commitment to enhance and strengthen trade with our key export markets around the world", adding: "It will provide a unique convening power to UK exporters and a secure sovereign hub for diplomatic events.

"The design and construction of the new national flagship will be a national endeavour and a chance to show off the very best of UK shipbuilding.”

The original Royal Yacht Britannia was ditched by the New Labour government in 1997.

Some Tory MPs have long lobbied for a new ship to take its place, with Johnson coming out in favour of the plan last summer.

Described as a “floating embassy”, the ship is expected to be paid for out of the Ministry of Defence budget, with costs soaring well above the original £200m projection.

The SNP said last year that the expenditure was "indefensible" in light of cuts to Universal Credit and other lifeline benefits.

Buckingham Palace also distanced itself from the plans. One senior royal source told the Sunday Times the ship was regarded as "too grand" a symbol to be used by the monarchy in the modern age. They said: “It is not something we have asked for.”

Since then the cost of living crisis has intensified, with Brexit, the Russian invasion of Ukraine and the pandemic adding further strain to household budgets.

Nevertheless, Johnson will hail the boat as a symbol of Global Britain.

He is expected to say on Thursday: “Shipbuilding has been in our blood for centuries and I want to ensure it remains at the heart of British industry for generations to come.

“The national shipbuilding strategy will transform this important and crucial industry, creating jobs, driving technology development and upskilling the shipbuilders of tomorrow, ensuring we are levelling up across every dock, port and shipyard in the UK.

“This will ensure the UK is rightly seen as a shipbuilding power across the world.”