Electric vehicle battery plants will have to be built “across the whole of the UK” just to satisfy the country’s domestic car production, the Prime Minister has said.

Boris Johnson also gave the clearest signal yet on Thursday that the Government will lend support to the building of one such facility – known as a gigafactory – in the West Midlands.

He said there is “obviously a case” for establishing one in the region.

Mr Johnson was speaking at the UK Battery Industrialisation Centre in Coventry, as plans were formally submitted for a power unit plant on a site located next door.

West Midlands Mayor Andy Street has described the proposal, which could create 6,000 jobs, as “mission critical” for the local economy and future health and prosperity of the region, and has said he “will not rest” until it is delivered.

Planning permission to build the 5.7 million square feet gigafactory would boost ambitions to keep automotive production at the heart of the West Midlands region, according to the joint venture behind the move.

Proposals for the site, which could create tens of thousands more jobs in the supply chain, were first unveiled in February.

UK electric automotive announcements have been coming thick and fast.

Last week, Vauxhall’s owner Stellantis said it would invest £100 million to build electric vans and cars at Ellesmere Port, in Cheshire, which would make it the first large plant in the UK dedicated exclusively to electric vehicles.

Earlier this month, Nissan set out plans for a £1 billion electric vehicle hub in Sunderland, including a gigafactory built by Nissan’s partner Envision, a battery recycling facility, and production of a new all-electric car model.

That followed an announcement in December that construction of a £2.6 billion gigafactory – mooted as the UK’s first – by start-up Britishvolt in Blyth, Northumberland, was due to start in the summer.

In February, the country’s biggest car maker Jaguar Land Rover (JLR) – whose headquarters are next door to the proposed Coventry site – said it would be an all-electric brand by 2025.

In a speech outlining his levelling up programme, Mr Johnson said: “We need these batteries, there’s absolutely no question.

“It’s great that Envision is bringing a gigafactory to Sunderland and we have high hopes of the BritishVolt plant in Blyth.

“But even those two together will only supply a fraction of the demand that the UK’s own domestic vehicle market will have.

“We’re going to need 70,000 skilled people just to make batteries across this country.

There's obviously a case for having a gigafactory here in the West Midlands.

“We want to work… to make sure we produce those gigafactories across the whole UK.

“There’s obviously a case for having a gigafactory here in the West Midlands.

“You’re going to want one next to a centre of automotive manufacturing, but even that won’t be enough to satisfy the demands, just for the UK domestic market.”

He added the UK could also “do much more” to source chemicals and metals in the UK, “to make sure this country retains its lead in devising ever cleaner, ever greener, more beautiful technology”.

Mr Street, who was among those listening to the speech, said it is “mission critical that the West Midlands secures a gigafactory” to safeguard its key industry, economy and the “future of our planet”.

Coventry City Council is submitting the blueprint in partnership with the operators of Coventry Airport, where the plant would be located, in a move that backers say could attract £2 billion in investment.

If plans are passed, the site could be operational by 2025, though it would need investment from the private sector.

Local government sources have said discussions are “well under way with a number of potential suppliers” to take on the plant, including established battery suppliers and car makers.

The Government has signalled its ambitions for a home-grown electric car battery industry in the UK, by making up to £500 million available initially to help build gigafactories.

UK policymakers also announced last year that from 2030, the UK will end the sale of new petrol and diesel cars and vans, a decade earlier than previously planned, as part of a 10-point “green industrial revolution”.

Midlands regional leaders are keen to attract electric car supply chain investment to the area, which is viewed locally as the historic heart of UK automotive manufacturing and employs thousands of people.

Asked by a journalist if he would “provide the cash” to help towards building a Coventry gigafactory, Mr Johnson joked there are “very few people in this country more successful in extorting massive cheques form the Treasury than Andy Street”.

Turning to look at Mr Street, in the audience, he then quipped: “I’m not certain that you’ve yet been to me with the request for a gigafactory, Andy.

“He’s now taking off his mask – very worrying development. I thought I’d got through this.”

Mr Street, answering the question, then said “a moment will come” when the request would be submitted to Government.

The Prime Minister added: “I look forward to receiving the request.

“But obviously the Government is there to support and to provide strategic direction and I hope it’s been clear, in everything I’ve said, that levelling up only works when the private sector comes in as well.”