NHS Trusts in England have seen their deficits grow to an eye-watering £822 million in 2014-15, compared with just £115 million the previous year.

Much of this rise in spending has been blamed on an increased use of agency nurses, according to new figures published from England’s health regulator Monitor.

The new data also showed that Foundation Trusts in England saw a deficit of £349 million, while other Trusts – such as for mental health and ambulance service – saw debt of £473 million.

The Department of Health said Trusts “needed to get better at balancing the books”, but Monitor is warning that figures for this coming financial year were “likely to be even worse”.

Foundation trusts run some hospitals, ambulance and mental health services, but they are not controlled by central government.

These figures come as new reports from healthcare think-tank the King's Fund show that the NHS will face a £30 billion funding gap by 2020 – something recognised by NHS England, which runs much of the health service.

The new Conservative government has pledged to try and plug this gap with a major increase in spending on the NHS, with planes to invest £8bn a year extra into the service by the end of the decade being put forward this month.

But the NHS must also make around £5 billion a year in savings across all sectors, especially hospitals, to try and keep the service in the black.