UK-based accountancy firm Moore Stephens has been appointed to investigate the rising costs of transforming the London Stadium from a track-and-field venue into English Premier League football club West Ham United’s home ground.

According to Sky Sports News, transformation costs at the site, formerly the Olympic Stadium, have reached £323m (€370.2 million), which is more than £50m above original estimates.

Late last year, Mayor of London Sadiq Khan ordered an investigation into the sharp increase, and has now appointed Moore Stephens to look into the costs as part of the wider project. The decision came after the London Legacy Development Corporation (LLDC) revealed that a large chunk of the rise in redevelopment costs for the London Stadium were due to problems surrounding the ground’s retractable seating.

Draft findings from the probe are set to be submitted to the Greater London Assembly by June of this year, with a public report scheduled for the summer.