A Brexit-backing hedge fund manager who earned £220m from the collapse of UK markets in the days after the EU referendum has now slumped to his biggest ever losses.

Billionaire Crispin Odey, who manages about £6.5bn for clients of Odey Asset Management, saw his fund lose 49.5 per cent of its value in 2016 as his ultra-pessimistic bets on the UK economy turned sour.

The outspoken financier was one of the most high-profile backers of the Leave campaign and predicted UK stocks would lose up to 80 per cent of their value amid a recession and higher inflation. The FTSE 100 has since surged to record highs.

Mr ​Odey, who last month complained that “mindless” passive investing was driving out active fund managers such as himself, steered his flagship European fund to a 3.4 per cent loss in December. The average for other similar funds during the month was a 4 per cent gain.

Jacob Schmidt, chief executive officer at investment advisory firm Schmidt Research Partners, told Bloomberg: “Even if his assessment is correct, the problem with ultra-bearish bets is the timing.

“As per JM Keynes, the market can remain irrational longer than you can remain solvent,” he said, referring to a comment by the famous economist. “Minus 50 per cent is a very serious drawdown.”

Hedge fund manager made millions betting markets would collapse after Brexit

Mr Odey had hailed his own performance after the Brexit vote. At the time he said: “This is a good day for me. I was brave. I had a lot of clients who were angry with me but they won’t be quite so angry this morning. Life is not about being un-brave at the right time. We in the City have certain skills.”

“There’s that Italian expression,” he told the BBC. “‘Al mattino ha l’oro in bocca’ – the morning has gold in its mouth – and never has one felt so much that idea as this morning really.”