 The Sessions House for the Middlesex Quarter Sessions was at Clerkenwell Green from the early 18th century.The quarter sessions at the former Middlesex Sessions House performed most of the limited administration on a county level until the creation of the Middlesex County Council in 1889.New Brentford was first promulgated as the county town in 1789, on the basis that it was where elections of knights of the shire (or Members of Parliament) were held from 1701.