Acute trusts without foundation status are increasingly putting staffing levels at risk by waiting too long to request temporary bank workers.

More than a fifth of all requests for temporary staff in the year to September 2011 were for shifts starting within 24 hours, according to a report by NHS Professionals, the NHS’s “in-house” bank service. In London, 31 per cent of requests were classed as “short notice”.

But leaving it so late to request staff makes it more likely that no one suitable will be found in time, the report warns.

A quarter of short notice requests go unfulfilled, it said.

Although the proportion of short notice requests fell in acute foundation trusts, it has risen among those lacking foundation status. These trusts have seen a 17 per cent increase in the year to September 2011.

Kevin Croft, president of the Healthcare People Management Association, which represents NHS human resources directors, said the figures suggested these trusts were trying to save money by delaying requests until they were absolutely certain they needed extra staff.

Many trusts have also responded to the financial pressures by requiring requests for temporary workers to be signed off by senior managers, potentially causing delays, he said.

While it was useful for trusts to take a “flexible” approach to staffing, delaying decisions too late could mean vacancies were not covered, he added.

NHS Professionals chief executive Stephen Dangerfield agreed the trend was due to the financial restraints.

He said: “It’s clear that with trusts focusing on efficiency, short notice shift demand is increasingly a fact of life.”

Overall demand for temporary workers was 9 per cent lower in foundation trusts in the year to September 2011, compared with the previous year, but 2 per cent higher among non-foundation acutes.

There were “rapid increases” in demand among acute trusts outside of London, with a 23 per cent rise in September 2011 compared with September 2010.

Mental health trusts had reduced demand by 14 per cent.

The proportion of all shifts filled by agencies, as opposed to NHS Professionals, rose by 4 per cent over the year in acute non-foundation trusts but fell  by 0.7 per cent in foundations and 5.7 per cent in mental health trusts.