Government plans to allow “any willing provider” to compete for most NHS clinical contracts could expose the health service to challenge under European competition law, experts warn.

The proposed reforms will, for most services, allow patients to choose any willing provider that meets NHS standards and prices.

But lawyers and academics warn that the changes will leave NHS commissioners and providers more vulnerable to legal challenge at the European Court of Justice.

Historically, European Community Treaty articles banning “anti-competitive agreements” and “abuse” of market dominance were held not to apply to the NHS. But legal experts say the greater use of competition in the NHS could bring more of its activity under the rubric of European Union competition law.

David Owens, head of the commercial department at law firm Bevan Brittan, said he had seen, in the past fortnight, a new claim by a healthcare provider arguing that a primary care trust was in breach of competition law for allegedly commissioning health services “unfairly”.

He told HSJ: “It’s going to be very difficult - the more you go down the route of any willing provider and open the competition process - to maintain the line that EU competition law, and all that goes with that, doesn’t apply within the NHS.”

Under the reforms, commissioners would face a “much greater risk of challenge” and “potential tensions” between “what might be best practice from a healthcare perspective” and what a competitive market might result in, he said.

The government has said any willing provider arrangements will allow commissioning consortia “the freedom to promote adoption of best practice”.

But University of London senior research fellow David Price said there was a danger the government’s planned quality controls would be overridden by EU law.

He said: “If [European private hospitals] come in, will the inspection regime that [all providers are] supposed to be under be regarded by the European Union as too burdensome? That may be subject to legal test [and] you might expect that the court will continue to move the goalposts.”

Anne Crofts, a partner in the commercial services team of law firm Beachcroft agreed that extending the any willing provider arrangements would make EU competition law “bite” in new areas of NHS activity.

But she added that competition law was “sophisticated”, and there were many cases where non-competitive arrangements had been allowed because they had been found to be “in the consumer’s interest”.

A Department of Health spokeswoman said the planned reforms were “entirely consistent” with EU competition law and were informed by legal advice.

She added: “Monitor will not have power to promote competition for competition’s sake and will only be able to intervene where it can demonstrate that restrictions on competition act against the public interest.”