Chancellor Rachel Reeves was flying to New York to promote London’s Square Mile as a “crown jewel” in the economy as she seeks to boost growth in Britain.
She set off for the trip to America and Canada as Labour banks on ratcheting up economic growth from the recent miserly levels to get more money to fund public services.
She was due to meet Wall Street leaders in New York and host a reception to celebrate women in finance.
The US is the UK’s biggest financial services trading partner, with UK exports to the US valued at £23.4 billion a year.
“The sector is at the heart of the government’s core mission to deliver sustainable economic growth as a jewel in the crown of the UK economy,” said a Treasury source.
Some economists fear the Square Mile, like some other parts of Britain’s economy, is suffering a “slow puncture” from Brexit, with financial services not part of the trade deal with the European Union.
The new Labour government is expected to seek closer ties with the European bloc, to mitigate the economic damage from splintering away from the UK’s biggest trading partner.
Ms Reeves has already moved to scale back road, rail and hospital building projects to plug what she alleges is a £22 billion black hole in the public finances, a claim rejected by her predecessor Jeremy Hunt, and which economists say was at least partly known before the July 4 general election.
She has also restricted the winter fuel payment so it only goes to pensioners on benefit and warned of tax rises in an autumn Budget, with more difficult decisions on public spending and welfare.
As she headed across the Atlantic, she stressed: “I’ve wasted no time in my first month in office in taking the difficult decisions necessary to fix the foundations of our economy, so we can rebuild Britain and make every part of the country better off.
“That means restoring economic stability so we can attract the investment needed to create good jobs, boost wages, and improve opportunity across Britain.”
She added: “There is no credible plan for growth without private sector investment. That’s why I’m breaking down barriers at home and banging the drum for Britain abroad as we gear up to host the International Investment Summit.”
In Toronto, she was due to mean clean energy and infrastructure experts as the Government seeks to make Britain a clean energy superpower.
Ministers have already taken steps to boost the number of offshore and onshore wind farms, as well as solar energy centres.
But the Government has been criticised for scaling back its £28 billion green economy masterplan amid the public finances crisis.
