Birmingham’s weak leadership means the city is set to lose key property assets such as parts of Longbridge, Edgbaston cricket ground and Pebble Mill, mayoral candidate Sion Simon has claimed.

Mr Simon, who hopes to win the Labour nomination to stand as city mayor in 2013, condemned the Government’s decision to sell off land currently owned by regional development agency Advantage West Midlands – with the proceeds going to the Treasury.

Local councils have been told they can buy the sites, but will need to pay market rates.

By contrast, Boris Johnson’s administration in London is simply to be given the assets owned by London’s development agency.

It will be free to keep them in public ownership or to sell them off and keep the proceeds to spend on new regeneration projects.

Mr Simon said: “The difference is that London has a powerful democratic voice in the form of Boris Johnson who cannot be ignored, while this government rides roughshod over Birmingham and its interests.”

It follows an announcement by the Department for Business, Innovation and Skills that 13 sites owned by Advantage West Midlands, the regional development agency, are to be sold off.

They include the site of the former BBC studio at Pebble Mill in Edgbaston and 3.7 hectares at Eastside, in Birmingham city centre, previously used by Mathew Boulton College.

The city council could buy the sites, but the Government has warned they must be sold at market value. It has ruled out “gifting” the assets to local authorities or allowing councils to defer payment.

Ministers are still considering the fate of other properties including three hectares of land surrounding Edgbaston Cricket Ground and four sites, comprising 23 hectares, at the former MG Rover plant at Longbridge.

However, they have already made it clear that they are unlikely to be handed over to local authorities or business groups at no cost.

By contrast, Ministers have ruled that sites owned by The London Development Agency – which is also being abolished – will simply be handed over to the Greater London Authority, led by London mayor Boris Johnson.

A Department for Business, Innovation and Skills spokesman said: “The London Development Agency is already a functional body of the Greater London Authority (GLA), and it is being folded into the GLA, so this is primarily a reorganisation of the GLA Group.

The GLA will inherit not just the LDA’s important portfolio of regeneration assets to support its new responsibilities for housing and regeneration in London. but also its significant liabilities, including long-term debt from its Olympic activities.

“All other regional development agency assets and liabilities will be disposed of through open market sales, other negotiated agreements or statutory transfer schemes. 

“There will be no automatic transfer of assets to any particular organisation – including local enterprise partnerships or local authorities because each regional development agency must be allowed to consider a range of strategic options with a view to securing the best outcome for both the local area and the public purse, and because state aid regulations must be complied with.”

Mr Simon said: “Why is the London Development Agency being folded into the Greater London Authority rather than just being scrapped like Advantage West Midlands?

“The answer is that London has a hugely powerful democratic voice who insisted on it, and who was too powerful to be ignored.

“The result is that these assets are going to remain under the control of the London administration.

“But in the West Midlands, the equivalent assets are going to be put up for sale - and it looks like the proceeds will just go to the Treasury.”

He added: “We don’t have a serious figure to stand up for us against the London government when these crucial decisions are being made. It means that London gets more and Birmingham gets less.”

According to Advantage West Midlands’ annual report and accounts for 2009-10, the agency had assets of £296 million and liabilities of £78.7 million. The value of its property portfolio is estimated at £106 million, according to figures published by the Department for Business, Innovation and Skills in December.