A trade union is urging the Government to “sack” Circle from Hinchingbrooke Hospital over financial issues though the private firm denies any crisis.

Tracey Lambert, Unison's eastern region head of health, has called on the NHS to call time on Circle's contract at Hinchingbrooke as the trade union expects Circle to reach a £5million threshold of support payments.

As part of the 10-year franchise, Circle has to supplement any loss Hinchingbrooke makes each year. So far Circle has paid £4.85m, just £150,000 away from a milestone at which point the Department for Health and Circle will renegotiate or end the contract – though both parties remain committed to the deal as reported in The Hunts Post.

Unison raises concerns that Hinchingbrooke faces penalty payments for failing to hit targets for accident and emergency waiting times, increasing the number of patients discharged at weekends and fines for patients infected with C difficile.

Unison believes the fines could push Circle over the £5m threshold.

However, Circle disputes it will cross that marker, saying it would have to announce any deviation from its half year forecast released in August as it is a publicly listed company.

Unison also highlights the hospital's spend on agency staff, which is expected to be about £2.4m by the end of the year, but Hinchingbrooke says, although it is higher than it would like, it is comparable to similar sized hospitals and is due to national guidelines which has increased the number of nurses needed on wards.

Ms Lambert said: “It is time for NHS England to step in and sack Circle. The whole franchise has been a farce from the beginning. The franchising experiment is now damaging staff, patients and the reputation of a previously well-respected hospital.”

A spokesman for Circle said: “We're a bit bemused, as we haven't changed our financial forecasts for the year, and Hinchingbrooke's clinical outcomes remain very strong.

“The hospital is a success story. We'd be happy to meet with Unison, as we're sure this is an honest misinterpretation of Circle's track record.

“NHS hospital finances are based on a system of fines and incentives from our commissioners. You can't take one set out of context and then make wild claims about the year-end position.”