A marsh controversially used as an Olympic training site is rotting four months after it was meant to be returned to its original condition.
Save Leyton Marsh campaigners have called on the Olympic Delivery Authority (ODA) to install new turf on the section of the public space used for a basketball training court last year before the Games.
But the ODA has refused – only promising to monitor it.
Waltham Forest Council granted planning permission for the ODA’s proposals only on the basis that the land would be returned to “pristine condition” by October 15, 2012 – a deadline which was not met.
Now campaigners have discovered the replacement turf is rotting because rainwater cannot drain away through replacement topsoil, which is too compact.
It is also gathering above a thin membrane put down by construction workers to prevent asbestos found in the soil from being dug up.
The lack of drainage means that the marsh is now waterlogged and no air can circulate through the turf, causing it to rot.
Campaign group spokeswoman Caroline Day said: “The turf is rotting, they have damaged our marsh.
“The turf really needs to be removed. We’re so far down the line from the deadline and the ODA can see there’s problems so it’s not clear why they aren’t returning.
“We’re angry and upset because they’ve failed in their promise to return the land to its former condition.”
Fellow campaigner Claire Weiss added: “It’s worse than leaving us with no legacy at all. The marsh is in a mess.”
An ODA spokeswoman said it has carried out the reinstatement plans agreed with Waltham Forest Council.
She added: “However, we continue to monitor the situation, and are in discussion with Lee Valley Regional Park Authority about a maintenance programme to achieve the best ground conditions possible, once the impact of heavy rainfall during the winter months has lessened.
“The whole of Leyton Marsh continues to be open to the public and used by local people.”