Cryptocurrencies, such as bitcoin, litecoin and dogecoin, are types of money that exist only as strings of computer code

Digital currency traders are hunting for £840,000 in missing bitcoins after the collapse of Moolah, an online cryptocurrency exchange, and the disappearance of its founder.

Alex Green, the chief executive of Moolah, has not been seen since Sunday when he wrote on his company’s website: “I know I have f****d up on a catastrophic level.”

Cryptocurrencies, such as bitcoin, litecoin and dogecoin, are types of money that exist only as strings of computer code. Bitcoin is the oldest, most popular and the most widely traded on online exchanges.

Moolah ceased trading last week, according to a post on its website that assured traders their money was safe.

However, Moolah users later highlighted the disappearance from the exchange of 3,700 bitcoins, worth £840,000. They claimed that