Opposition councillors have called for a formal investigation into claims that Barnet Council paid £13.5m for a site bought last year for £750,000.

The authority plans to use the Abbots depot, in Oakleigh Road South, New Southgate to store its rubbish trucks, a bulking facility and a fuel station when it moves out of its Mill Hill depot next year.

People living nearby fear the plans will create noise and traffic problems.

Councillors voted in December to buy the site for £13.5m, after being told it cost £8m a few years before.

But Labour councillors claim key information was not provided before the vote, and have called for an investigation.

Woodhouse councillor Geof Cooke said officers have confirmed the Abbots depot was bought in June 2014 by property company Cergold for £750,000.

He said part of the site is also being used informally by the Winters Haulage company – despite councillors being told the site was vacant.

Cllr Cooke said he had complained to the council’s chief executive and asked for a formal investigation.

He said: “This information should have been provided to councillors before they were asked to vote on the purchase of Abbots Depot – at both committee stage and when it came up at full council on two occasions.”

Cllr Cooke thanked residents for their “hard work” in uncovering information to challenge the council.

A spokesman for Barnet Council said: “The council agreed to purchase the Abbots Depot site for £13.5 million based on market value and a detailed business case. No additional premium has been paid to secure vacant possession of the site.

“In addition, in response to residents’ concerns about heavy goods vehicle movements along Oakleigh Road South, the council has purchased the lease for the adjacent Winters site, which will result in an overall reduction of HGV movements.

“The £750k figure quoted does not reflect the open market value of the Abbots Depot site. We are happy to discuss the matter further with Cllr Cooke and will investigate as appropriate.”