UnitedHealth has been awarded a second contract to run a GP surgery in Derbyshire and contracts to run three surgeries in north London.

The multinational's first contract with Derby City primary care trust was subject to months of legal wrangling in 2006 after opponents sought, and ultimately failed, to block the involvement of the private sector through the courts.

But just over a year later, the PCT noted that UnitedHealth had "exceeded delivery against their contractual obligations" in running Normanton Medical Centre. Previously the medical centre had had no permanent clinical staff, but PCT board minutes noted that a year into the contract, the centre had recruited two full-time GPs and had increased its list size in the deprived community by 30 per cent.

The centre has also recently extended its opening hours to 8pm, Monday to Friday.

Last week UnitedHealth was awarded its second GP practice in Derby - taking over a single-handed practice at the Vidya Medical Centre. At the same time, it was awarded three practices in deprived areas of Camden in London.

The move provoked further controversy in London as UnitedHealth was rumoured to have bid to run the practices at 25-30 per cent below the costs proposed by local GPs. This led to accusations that Camden PCT had awarded the contract on the basis of the lowest bidder and that the company had underestimated its costs.

UnitedHealth would not confirm the contract values, but Camden PCT chief executive Rob Larkman aid: "This has been a very rigorous process, and we are satisfied that Camden PCT has secured excellent services for the patients of these three practices."

UnitedHealth director of primary care Dr Peter Smith said: "We are keen to build on the existing strong provision and develop additional services for patients and the local community."

A spokesman for the campaign group Keep Our NHS Public said: "UnitedHealth's profits are astronomical and that is its only interest. But the money for these profits has to come from somewhere and this means that patients will suffer."