Two of the UK’s most prolific ticket touts have been found guilty of fraud, in an important case that could have significant implications for people who buy tickets to sell them for profit.

Peter Hunter and David Smith, trading as Ticket Wiz and BZZ, used multiple identifies and bots to buy £4m worth of tickets to events including gigs by Ed Sheeran and Taylor Swift as well as West End shows such as Harry Potter and the Cursed Child. The pair sold them on secondary ticketing websites for £10.8m, jurors at Leeds crown court were told.

During the three-month trial, prosecutors described the married pair as “dishonest fraudsters motivated by greed”. They were found guilty of fraudulent trading and possessing an article for fraud on Thursday.

The verdict comes after the Guardian exposed Hunter as one of the most powerful ticket touts in the UK, as part of an investigation into secondary ticketing.

Two of the sites, GetMeIn and Seatwave, have since been closed down. The two largest players, StubHub and Viagogo, are still trading despite multiple complaints from consumers, the condemnation of MPs and an abortive lawsuit against Viagogo from the consumer regulator.

Touts use secondary ticketing websites as a platform to find buyers for tickets they have bought through primary sites, such as Ticketmaster.

The Guardian has previously reported that touts are using multiple credit cards, false identities and software including bots to snap up as many tickets as possible, making it harder for genuine fans to get their hands on them.