NHS England wants independent auditors to look into possible overcharging by London specialist trusts.

A contract notice published earlier this month said in 2017-18, “a number of major acute contracts are financially overperforming by significant sums, above the agreed contract plan values”.

The clinical audit will make recommendations on whether trusts have breached their contracts.

The tender notice said NHS England London’s analysis had identified the issue but it was now looking for a more detailed examination of multiple service lines at “one or more providers”.

NHS Improvement data released earlier this week showed London trusts were predicting a combined year end deficit of £312m – £119m worse than planned. King’s College Hospital Foundation Trust showed the biggest decline against plan in the country, with its position deteriorating by £54m.

London specialist trusts used to receive Project Diamond funding from the centre to reflect the complexity of the treatments they offer. The loss to providers was supposed to be remedied by a new clinical coding system, however HSJ understands some trusts believe this has not happened.

The contract notice said: “While some areas of the overperformance are driven by activity increases and include known and agreed adjustment items for payment to trusts, a number of areas appear to be driven by average unit price increases across multiple service lines that may be due to changes in counting and coding practices at trusts for which prior contractual notices have not been served in advance.

“There are also some service areas that are activity driven where the counting of activity appears to have materially increased from what was in the contract plans, which is also adding to the over performance positions at several trusts.”

Bidders must apply for the £50,000 contract by 26 February.

The contract specification said the work must be delivered for “the first two trusts being investigated” by 30 March.

A spokeswoman for NHS England said: ”The annual 2017-18 budget for specialised commissioning services in London is approximately £4bn. Current financial forecasts predict no overspend.

”We are unable to name the NHS trusts who may be undergoing an audit of their NHS contracts as this information is commercial in confidence.”