ReThink saw "weak employment in the public sector for some time to come". The "irony", it said, was "that sensible investment in IT could see the public sector cut substantially into its cost base".

Major government projects involving the heavy use of IT contractors, that have been cancelled over the last two years, include the NHS national electronic database, second generation biometric passports, the ID cards programme, the Contact Point child protection database, and the development of new defence technologies.

Bennett said: "With such low levels of IT investment in the public sector there seems little alternative but to switch."

IT remains a better sector than many others for recruitment, however. The growth in IT jobs that of the overall jobs market, according to the monthly Recruitment and Employment Confederation (REC) and KPMG Report on Jobs. The fastest growing sectors for recruitment were IT and engineering and construction.