Last updated on .From the section Football

West Ham United moved to the London Stadium from Upton Park in August 2016

The chairman of Olympic Stadium operators the London Legacy Development Corporation has resigned amid the row over the escalating cost of converting the venue into a football ground.

David Edmonds has stepped down two days after London Mayor Sadiq Khan ordered a "detailed investigation" into the cost of West Ham's new home.

The outlay to modify the stadium has risen from £272m to £323m.

Edmonds was appointed chairman of the LLDC in September 2015.

He has been a board member of the Olympic Park Legacy Company and its successor, the LLDC, since 2010.

Edmonds chaired the investment committee, and was the first chair of E20 LLP, the joint venture between LLDC and the London Borough of Newham, owners of the Olympic Stadium.

"David has made an enormous contribution to the legacy of the London 2012 Games and he has helped to steer the organisation through some extremely challenging issues," said David Goldstone, chief executive of the LLDC.

Campaigners have welcomed the investigation into the £50m rise in costs.

Part of the reason for the increase is a rise in the cost of installing and operating the retractable seating, which can be removed for concerts and athletics events.

The cost of £8m a year is up from an estimated £300,000 because the company originally contracted for the job had gone bust, reports BBC sports editor Dan Roan.

Stadium operators LLDC and the London taxpayer will need to pick up the additional costs.

Premier League club West Ham contribute £2.5m-a-year rent, plus the one-off £15m for the conversion.

West Ham won the bid to occupy the Olympic Stadium in March 2013, and played their first game there in August 2016, after 112 years at Upton Park.

However, their move has been marred by fan violence, leading the club to issue a five-point security plan to prevent further disorder.

In addition, police will be helping stewards to segregate fans inside the ground at West Ham's match against Stoke City this weekend - the first time this has been done at the stadium.