The cost of converting the London Stadium from a football ground to multi-use venue and back again has risen to £6million.

The Independent reports the stadium’s owners E20 have confirmed – via a Freedom of Information request from PA – that it had cost £11.3million to move the seats in 2017, when the stadium staged the World Athletics and World Para Athletics Championships.

In its  recent set of accounts, that E20 is losing £20million a year and has spent £4million in legal fees in an unsuccessful attempt to get more money out of West Ham.

The Hammers have regularly argued that they are not responsible for the financial woes and eventually peace broke out between the two sides last year after a series of abrasive conflicts.

The key issue is the cost of moving its seats after the football season is over so it can be used for athletics, music concerts and other sporting events over the summer.

The Independent adds the figure fell to £4.1million, though, in 2018, when the stadium was the venue for concerts by the Rolling Stones, Jay Z and Foo Fighters, before hosting three weekends of international athletics.

But the cost of moving the seats has risen again this year after a summer that has seen the stadium stage a concert by rock band Muse, two Major League Baseball games and athletics’ Anniversary Games on July 20-21.

The £6million figure in E20’s FOI response is £500,000 higher than an estimate it published earlier this summer and it includes a £1.9million cost for the New York Yankees v Boston Red Sox series.

E20, however, told PA that MLB’s hire fee for the stadium covered the cost of the seat moves and the league also covered the costs of the baseball pitch and “overlay”, the temporary structures such as the bullpen and dugouts.

Asked if the baseball experiment, which is being repeated next June, made money, an E20 spokesperson said: “In addition to the wider economic benefit of bringing MLB to London, I can confirm a profit was generated by the baseball games.”

The publicly-owned company would not reveal how much profit was made, though, citing “commercial interests”.