Recycling giants Powerday may continue their fight to build a waste plant of Yiewsley, after the Mayor of London refused to get involved.

The firm's hopes of resurrecting their bid to build a waste facility in the Old Coal Yard off Tavistock Road were in the Mayor's hands, after the borough refused their planning application in December last year.

The original Powerday proposals were for a facility with an annual capacity of 950,000 tonnes of waste, of which 600,000 tonnes would be transported by road.

At the crunch meeting at the civic centre in December, Powerday announced out of the blue that they would reduce the capacity by nearly half, to 450,000 tonnes, and an adjournment was requested and denied.

Being an application of potential importance for London, the proposal was then referred to Mayor Boris Johnson, who could have chosen to take it over and have the final say, but instead let Hillingdon council's decision stand.

A Powerday spokesman said: "Powerday is obviously disappointed that the Mayor has not decided to call in the application to be determined by him and frustrated that Hillingdon’s refusal to accept the amended proposals...could not be considered by the Mayor.

"Powerday will now be consulting its legal and planning team prior to determining whether or not to appeal the decision to the Secretary of State."

The Mayor's reluctance to intervene has come as good news for the Garden City Estate Residents’ Association (GCERA), who collected nearly 4,000 signatures over eight petitions in a highly-organised campaign.

Jan Sweeting, GCERA secretary, fears that there will be a two-pronged offensive by Powerday.

"We are concerned that they will now just raise the stakes, by appealing the refusal of the 950,000 tonnes capacity application, as well as submitting a new planning application for a reduced capacity.

"Even with half the rubbish, there will be all the same problems. A lot of the activity on site will no doubt happen outside the buildings.

"We will continue with the fight, and we will be prepared for whatever happens next."