Revelation comes amid mounting concern over online prediction market’s effects on integrity of financial system

UK authorities are being urged to intervene after it emerged that the online prediction market Polymarket has been taking thousands of dollars worth of bets over whether HSBC and Lloyds will fail.

Polymarket – the US-owned company which holds bets on anything from football matches, to the existence of aliens, to when a bomb drops on a city – has allowed users to take $77,507 (£58,530) worth of positions on whether the world’s biggest banks will go under by the end of this year.