The average town hall staff salary was £21,588 in 2007, according to research by the Improvement and Development Agency. Data published by the agency last month also showed that the total gross pay bill for local government last year was £26.2bn. The IDeA's annual salary survey has been beefed-up this year and, for the first time, included detailed assessments of individual local government posts. The change meant researchers calculated data based on 870,000 individual employee records, compared with just 8,000 cases last year – providing more robust figures. Below senior levels, which have been detailed in a separate annual study, the highest annual earners were solicitors (£35,452), followed by child protection advisers (£35,047), architects (£32,546), and ICT professionals (£32,825). Shire counties accounted for the largest chunk of the salary bill (£7.2bn of basic pay), followed by metropolitan districts (£6bn) and English unitaries (£4.1bn). The agency's figures also laid bare local government's lingering gender pay gap. The median basic pay rate for full-time female staff was £20,895 compared with £22,293 for men. A senior Treasury source said: ‘Local government's gender pay gap is lower than experienced across other sectors of the UK economy, but… more needs to be done to reduce it further or wipe it out.'