Shachar Bialick, the founder of payments fintech Curve, which launched in the UK in 2016, added that “within a year or two, you’re going to see more companies failing”.

“Those companies will either [be] unable to bring in talent or the cost structure will become higher to compete with the likes of Google,” he told  City A.M.

The warnings come as the Chancellor, Rachel Reeves, rolls the turf for a sweeping round of hikes at her first budget in October. While the government has ruled out raising income tax, national insurance, and VAT, she has repeatedly refused to deny that it will lift the charge on capital gains.

Currently, the rate sits at 20 per cent on all chargeable  assets   other than residential property, where the charge is 24 per cent. In contrast, the highest rate of income tax is 45 per cent.

Treasury officials have reportedly been drawing up plans to equalise the two. Such a move could raise as much as £16bn, according to researchers at the University of Warwick.

A Treasury spokesperson said, “The Chancellor has been clear that difficult decisions lie ahead”.

Innovate Finance, which represents more than 250 fintech companies, cautioned against the move yesterday and said the Treasury should recognise that “not all capital gains are equal”.

“Significant increases to CGT could risk undermining the Chancellor’s growth agenda,” Innovate Finance boss, Janine Hirt, told  City A.M.  

“The competitive nature of the UK’s capital gains regime is a powerful incentive for entrepreneurs to choose the UK to start and grow their business – attracting and retaining the talent that creates the businesses that are global champions.”

In a report this week, the Resolution Foundation suggested a range of reforms to the levy, including aligning  CGT   rates for shares with dividend tax rates; taxing property capital gains like wages; and introducing CGT exit charges when moving country could raise anything up to £12bn.