Decision by US bank’s CEO Jamie Dimon followed trip to New York by top adviser to Keir Starmer

The boss of JP Morgan Chase signed off on a new £3bn tower in London after a trip to New York by a top adviser to the UK prime minister to give assurances about the government’s pro-business policies, it has emerged.

The Wall Street bank, which along with Goldman Sachs announced substantial investment plans in the UK hours after they were spared tax increases in Rachel Reeves’s autumn budget, only signed off on the plan for its new UK headquarters last Friday.