A farmer has expressed concern after Bradford Council closed off one of his fields, telling him it contained landfill gas.

Contaminated land at East Manywells Farm, Cullingworth, which lies next to the controversial Manywells tip, has now been closed off for an indefinite period.

Farmer James Lawn is also worried that water in the area could be contaminated. No tests have been conducted at the nearby Manywells Beck for three years.

In the past few years, rows of trees between the farm and quarry have died, while grass in one of Mr Lawn's fields turned yellow one summer.

Mr Lawn, who is also a Cullingworth parish councillor, said: "I first noticed the problem a while ago. When they installed a generator at the landfill site, the whole field went yellow.

"Three or four weeks ago, a chap from the council turned up and just closed the field off. They said the hollows in the field contained landfill gas.

"It's just an inconvenience. I have another field behind it but obviously I can't use that now either. It seems strange that they've just closed one field off -- the gas is unlikely to be restricted to one area."

Mr Lawn used the field for grazing cattle in summer and sheep in winter.

Bradford Council bought the Manywells landfill site in January for £500, claiming it would enable it to kick-start a £5.8 million remediation scheme.

Parish councillors have criticised the lack of communication with Bradford Council, claiming they were unaware the council needed to purchase the site to proceed.

When the contractors went into liquidation in 2002, the land passed to the Crown.

Chris Whitam, principal environmental protection officer at Bradford Council, said: "The field has been found to be contaminated land because of its potential to hold carbon dioxide gas from the neighbouring Manywells landfill.

"There are a number of low-lying hollows in the field which may, in extreme circumstances, fill with landfill gas and cause asphyxiation.

"We monitor the landfill gas around the site every week and so far there is no evidence the landfill gas is reaching the hollows.

"But the precautionary warning signs will stay in place until all remediation work has been done at the landfill, which could be two to three years.

"Manywells Beck was sampled previously by the Environment Agency and we have no concerns about the water quality and we are also regularly monitoring the condition of water within the area of the landfill."