The competition watchdog has launched an investigation into the Oasis ticket sales fiasco. The Competition and Markets Authority (CMA) will investigate Ticketmaster’s handling of sales for the band’s forthcoming tour, including how “dynamic pricing” may have been used to adjust the price. Initial excitement about the Gallagher brothers’ reconciliation soon gave way to dismay and outrage last weekend after fans complained that the prices for the 17 shows were increased without warning. The CMA had said on Tuesday it was “urgently reviewing” the use of dynamic pricing after criticism of the “scandalous” price inflation. The brothers said on Wednesday that they had no input into how the tickets were priced. The CMA’s investigation will consider whether Ticketmaster had engaged in unfair commercial practices and if clear and timely information was given to explain that the tickets could be subject to “dynamic pricing”. It will also examine if consumers were put under pressure to buy tickets within a short period of time – at a higher price than they understood they would have to pay. On the CMA’s website, fans are being asked to provide their evidence and, where possible, to include any screenshots they may have taken as they progressed through the buying process. Evidence can be provided using an online form. The authority said it would now engage with Ticketmaster and gather evidence from various other sources, which may include the band’s management and event organisers. A furore erupted at the weekend after fans of the Manchester band told of their anger after queueing online for hours only to find that the price of the £135 standing tickets had risen to £355 for the shows. Sarah Cardell, the chief executive of the CMA, said: “It’s important that fans are treated fairly when they buy tickets, which is why we’ve launched this investigation. “It’s clear that many people felt they had a bad experience and were surprised by the price of their tickets at checkout.” “We want to hear from fans who went through the process and may have encountered issues so that we can investigate whether existing consumer protection law has been breached.” It should not be assumed that Ticketmaster has broken consumer protection law, the CMA stressed. The review was welcomed by the prime minister, Keir Starmer, according to his spokesperson, who said No 10 would await its conclusions. “Ticketing platforms should be transparent with customers over how they price their tickets so people can make informed decisions,” said a Downing Street spokesperson. A spokesperson for Ticketmaster said: “We are committed to cooperating with the CMA and look forward to sharing more facts about the ticket sale with them.” The company, which is owned by the US entertainment firm Live Nation, has previously defended its dynamic pricing model – similar to that used by hotels and airlines – and said it did not set any ticket prices. Ticketmaster has argued that the system is designed to discourage ticket touts by setting prices closer to market value.