Brexit is killing finance job vacancies in London
Finance vacancies fell in every region in July and August, according to the Institute for Public Policy Research, an influential think tank.
London saw a 13.6% drop in job adverts, including for administrators, managers, and chief executives.
"This is striking as it is the only year in the past four where this trend has occurred," the IPPR said.
The number of people applying for finance jobs in Dublin rose by 800%, according to staffing and recruitment firm Manpower.
The lack of certainty over the City of London's so-called financial services passport, which allows banks to sell their services to customers from the European Union, has damaged confidence in the capital's jobs market.
And no coherent plan to manage the UK's exit from the European Union has emerged so far.
On Thursday, Foreign Secretary Boris Johnson said that Britain will start the exit process "by the early part of next year." But Prime Minister Theresa May rebuffed the comments, saying there was no commitment to any timetable.
"This new data shows the immediate impact that the vote to leave the European Union appears to be having on the finance sector," said Clare McNeil, associate director for work and families at IPPR.
"The Prime Minister needs to end doubts around whether the Government will pursue access to the single market and passporting rights as high priorities in the Brexit negotiations," McNeil said.