American bosses are reconsidering their UK investment plans after Rachel Reeves launched a £25bn tax raid on employers, a transatlantic trade body has warned.

Duncan Edwards, the chief executive of British American Business, said the Chancellor’s move to increase National Insurance (NI) costs had made the UK “less attractive”.

As a result, he said his lobby group’s members were now looking to alter their plans amid the threat of higher costs.

“For the UK leaders of American-owned companies looking to get more investment from their head office, their task has definitely just become more difficult as the costs of doing business in the UK will rise,” said Mr Edwards, whose organisation represents more than 400 companies doing business in both the UK and the US.

“Coupled with the Employment Rights Bill, this will make the UK less attractive for big American employers.”

It comes just days after Ms Reeves unveiled her £40bn Budget tax raid, which includes a proposal to raise NI contributions from 13.8pc to 15pc in April.

As part of the plan to raise £25bn from employers, the Government is also lowering the level at which businesses have to start paying NI from £9,100 to £5,000.