Viagogo has been ordered to publish data of its sellers by midnight tonight (Thursday), though it briefly disclosed the details of two major touts this week.

The controversial ticketing website will release full data about its sellers who have identified themselves to the platform under the terms of a court order secured by the Competition and Markets Authority (CMA) last year, demanding greater transparency for consumers.

Earlier this week, however, Viagogo briefly revealed details of some of its listed touts, before the data disappeared again.

North Financial Group, a company run by Andrew Newman, one of Britain’s biggest touts, was one of those disclosed.

Another was Margaret Canty-Shepherd, whose husband, Terry, was imprisoned over a £5m (€5.7m/$6.5m) fraud in which 10,000 people were sold fraudulent tickets. The parents of Olympic swimmer Rebecca Adlington were one of the victims of his fraud, and they ended up missing one of her gold medal swims at the Beijing Olympics in 2008.

Many more details of sellers and touts are expected to emerge on Friday if Viagogo complies with the CMA’s demands in full.

Claire Turnham, MBE and founder of campaign group Victim of Viagogo, said the details released so far are already causing concerns.

She told the Guardian newspaper: “As the few seller identities released so far include a super-tout, we have to wonder what horrors will emerge when Viagogo publishes fuller details on Friday, assuming it complies.”

A spokesperson for Viagogo said: “We fully intend to comply with the agreement that we reached with the CMA and we are working tirelessly to ensure we meet the deadline.”

Andrea Coscelli, the chief executive of the CMA, said: ”We will not hesitate to take further action if any of the sites fail to meet their obligations.”

Both Canty-Shepherd and Newman declined to comment to the Guardian.