The Competition & Markets Authority (CMA) has forced secondary ticketing operation StubHub to add a warning on its UK website that tickets resold via the platform may be invalid.

The competition regulator said it had raised concerns over “misleading messages about ticket availability and the use of adverts for event listings on overseas events that may not have been compliant with UK consumer law”.

The CMA said it was satisfied StubHub is now “adequately” warning people tickets bought on the UK site may not get them into an event, has removed inaccurate messages about ticket availability, is ensuring people know exactly where they will sit in a venue and is taking sufficient steps to ensure that the full addresses of business sellers are displayed.

Adam Webb, campaign manager for anti-touting pressure group FanFair Alliance said, “It’s welcome that StubHub are now apparently compliant with laws they signed legal undertakings to obey back in April 2018, and I hope this means the CMA’s stretches resources will now be fully focussed on Viagogo – a company that exists solely to promote large-scale ticket touting, and which should have faced court action years ago.”

Separately, the CMA is undertaking a Phase 2 in-depth investigation into the $4.05 billion (£2.91bn) acquisition of StubHub by Viagogo. It said the merging of Viagogo and StubHub, previously owned by eBay, which collectively represent 80% of the UK’s ticket re-sale market, could result in increased prices and reduced choice for consumers.

It emerged last month that Viagogo offered to sell off StubHub’s European business in bid to gain approval of the merger by UK regulators and avoid a Phase 2 investigation.