Eastbourne Borough Council commissioned the renewable technology project to benefit Kings Park residents living in fuel poverty, where more than 10 per cent of the household income is spent on fuel.

A council spokesman apologised for the delay and said, "It is unfortunate that the work at Kings Park has not gone entirely to plan, however this is due to unforeseen circumstances, in particular the sub-structure of the ground.

"A test drill was carried out but the ground sub-structure has been more difficult to work with than the test drill originally showed."

The contractors need to drill down 80 metres to put in the pump and have been working from 10am to 6pm, as agreed with people living nearby, but last week overran until 10pm, trying to prevent the hole from collapsing.

"It did anyway, as can often happen when deep drills are stopped halfway through.

The council spokesman said, "This work is part of the council's wider programme to promote the use of renewable energy, which is the ideal solution for people suffering from fuel poverty.

"We are aware that the people who live in Kings Park are off the gas network so will pay more for their fuel than other residents of Eastbourne and that people have been suffering from excess cold.

"This work is pioneering and if successful should provide a positive platform for the roll out of renewable technologies in the area."

The work will help the authority decide if ground-source heat pumps can work in Eastbourne's climate and with its soil type.

The decision to pilot the pumps at the former holiday park was taken with Kings Park Management Company, a not-for-profit organisation staffed by voluntary residents who maintain Kings Park properties for a regular fee.

Tony Land, a director of the company, said residents had been informed of the work more than two weeks before it began in a newsletter and only one of the 183 households had complained.

Mike Bloom, Liberal Democrat borough councillor for Sovereign, said, "I am pleased Eastbourne is the lead partner, with Wealden, Rother and Hastings, in introducing this kind of renewable energy.

"We are leading the way in the South East."