The UK will benefit from almost £18bn of extra private investment from Japan, Rishi Sunak announced during a visit to the nation for the G7 summit.
Speaking from Tokyo, the prime minister said the pledges are a "massive vote of confidence" in the British economy and will "create hundreds of good paid jobs".
While he painted an optimistic outlook for the national finances, he acknowledged "concerns" within the car industry following warnings of an "existential threat" posed by a looming Brexit trade deal deadline - and revealed he is in talks with the EU over how to address them.
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Speaking to broadcasters on board the JS Izumo aircraft carrier, Mr Sunak said: "It's something that car manufacturers across Europe, not just in the UK, have raised as a concern.
"And as a result of that we are engaged in a dialogue with the EU about how we might address those concerns when it comes to auto manufacturing more generally."
It comes ahead of the PM hosting a reception of business chiefs in the Japanese capital on Thursday, seeking to foster closer ties.
He expects to meet bosses of Nissan, Toshiba and Mitsubishi Estate, as well as representatives from UK firms Octopus Energy and Mott MacDonald.
Nissan has issued warnings about the costs of manufacturing electric cars at its Sunderland plant because of high energy costs and inflation.
Vauxhall's parent company Stellantis said on Tuesday that it will be unable to keep a commitment to make electric vehicles in the UK without changes to the EU trade deal as a tariff deadline approaches.
On concerns about UK battery-making capacity, Mr Sunak said: "Nissan have invested a billion pounds in battery manufacturing capability in the North East.
"I'll be talking to the Nissan CEO and other Japanese business leaders later about investment into the UK."
Downing Street said the £17.7 billion of new investments in businesses and projects in the UK will create high-skilled jobs and drive innovation.
Investment will be coming from the likes of property companies Mitsubishi Estate and Mitsui Fudosan, trading house Marubeni, and Kawasaki Heavy Industries.
The Marubeni trading house intends to sign plans envisioning spending around £10bn in the UK to boost offshore wind and green projects in Wales and Scotland, Number 10 said.
A £4bn expansion of UK offshore wind projects off Suffolk and Norfolk by the Sumitomo Corporation was also billed.
Companies based in the UK, such as Octopus Energy and Mott MacDonald, will send money back the other way.
"These new investments are a massive vote of confidence in the UK's dynamic economy, from some of Japan's top firms," the prime minister said.
Mr Sunak envisioned even greater ties will come after the UK joins a Pacific trading bloc, saying the "sky's the limit".
Earlier this year it was announced that the UK would join the bloc, which consists of countries including Australia, New Zealand, Canada, Chile and Japan.
Mr Sunak's trip to the G7 summit in Hiroshima will also include discussions on Ukraine and the Indo-Pacific.
He will unveil a new agreement with Japan to foster closer defence, security and cyber ties amid growing concerns about the threat from China.
The "Hiroshima Accord" will be formally agreed on Thursday and include a commitment from the UK to deploy a naval battle fleet in the Indo-Pacific in 2025 and to double UK troop numbers in upcoming joint exercises.
The prime minister will also agree to launch a partnership on semiconductors in order to reduce the reliance on Beijing for the supply of the essential microchips
A new cyber partnership will be announced to deepen co-operation, as will plans to accelerate use of clean energy.