The going rates for the health service’s most highly paid interim executives have been revealed as a result of a Treasury review of how public sector executives are employed.

HSJ’s exclusive analysis of data collected for the review of tax arrangements has found that at the start of 2012 the NHS was paying 48 off-payroll executives daily rates totalling around £44,000 a day. There is no suggestion that any of them were attempting to avoid tax.

Of the 55 off-payroll NHS executives identified in the review, 15 cost £1,000 or more a day – many of them working in England’s most financially challenged NHS organisations.

HSJ’s investigation confirmed that the most highly paid interim at the time was £2,000-a-day Mark Davies. Mr Davies was appointed interim chief executive of Imperial College Healthcare in May 2011 after the trust had announced it faced a £40m funding gap for the financial year.

To the end of February this year, Mr Davies worked 158 days at Imperial, suggesting a cost to the trust of £316,000 for around 9.5 months’ work. He has since become permanent on an annual salary of £260,000. A spokeswoman for Imperial said he had been engaged as an interim to “secure a leader of his seniority and capability at very short notice”. She added that Mr Davies was running “one of the biggest and most complex trusts in the country” at a “critical time when the trust faces huge challenges in terms of operational and financial performance”.

He was followed in the rankings by interim chief executives Neil Goodwin, on £1,750 a day at North Cumbria University Hospitals Trust, and Ian Wilson, on £1,500 a day at South West London and St George’s Mental Health Trust.

Mr Goodwin was engaged to lead North Cumbria – which needed around £28m financial support in 2011-12 – through plans to seek a merger with a foundation trust. He aims to leave by September this year.

He told HSJ this was the first and only interim management role he had done through his company GoodwinHannah, which has been established for six years providing mainly consultancy work.

Jim Birrell – who did a six-month stint as the Birmingham and Solihull cluster’s director of delivery – was both the most costly primary care trust interim and the most expensive interim not working as chief executive. A spokeswoman for the cluster said the “specific skills” he brought to the part-time role had helped it move from “a deficit of £55m at the start of the year to a small surplus of £2m at the end”.

Executive recruiter Rob McCargow, a managing partner at Cadence Partners, said there was a shortage of candidates for interim roles and that organisations in difficulty were a “less attractive proposition” for executives, especially compared to buoyant job markets overseas. For trusts facing merger or reconfiguration, it was not “economically viable” to appoint substantive directors only to have to “pay them off in a year or two”.

Despite this, daily rates had “decreased significantly” in recent years and now compared “more favourably” with total remuneration packages for substantive chief executives.

He added: “What these figures don’t show are the often significantly greater day rates charged by consultants who don’t hold formal management titles. Some of those are on day rates of as much as double the highest rate quoted in this table.”