Special commissions for securing (inter alia) the banks of the River Thames and its tributaries were issued during the mediaeval period in times of emergency. In 1427 a year of 'unseasonable weathering' (Stow's Chronicle) an Act of Parliament ordained that during the ensuing ten years 'several commissions of sewers' should be made 'to divers persons' 'to be sent into all parts of the realm where shall be needful'. Similar Acts were passed in 1472 (Act 6 Hy. VI c.5), 1487 and 1514. In 1530 another emergency occurred. It is referred to in the Grey Friars Chronicle - "this yere was gret wyndes and fluddes that dyde moohe harme". In the following year an Act (Act 23 Hy. VIII c.5) was passed which gave general statutory authority for the issuing of Commissions of Sewers whenever they might be required throughout the country. The provisions of this Act with only slight modifications governed the work of the Commissions of Sewers until the 19th century. Commissions were appointed for periods of 3 years (extended to 5 years in 1549 (Act 3 and 4 Ed. VI c.8) and 10 years in 1570 (Act 13 El. c.9). They were required to summon jurors to report on the state of embankments, streams and sewers and the names of landowners or tenants in the locality. It was their duty to repair walls, clean sewers and ditches and remove impediments to the free passage of water and they were authorised to appoint bailiffs, surveyors, collectors, clerks and other officers and to collect taxes or rates to cover the expenses. Except within the City of London after the Great Fire and in Holborn and Finsbury in connection with the development of the prebendal estate of Halliwell and Finsbury none of the London Commissions obtained statutory powers to construct new sewers until the early years of the 19th century.
In one respect the London Commissioners of Sewers had more extensive powers than those of the rest of the country. The 1531 Act was interpreted as applying only to navigable water courses or to those flowing directly to the sea. In 1605 an Act (Act 3 Jas. I c.14) was passed giving Commissioners of Sewers control over all watercourses and ditches within 2 miles of the City of London flowing into the Thames and a clause in an Act of 1690 (Act 2 Wm. and M. Sess.2 c.8) also included newly constructed drains and sewers within the area covered by the Bills of Mortality within their terms of reference.
None of the pre-18th century original Letters Patent appointing Commissions of Sewers in the London area has survived and, since early in the reign of Elizabeth I the practice of enrolling them on the dorse of the Patent Rolls lapsed and the series of Crown Docquet Books begins only in the last years of her reign, it has not been possible to trace with certainty the beginnings of the Commissions. There is however no doubt that the earliest was the Surrey and Kent, as a Commission was issued for this area in 1554, the only one which has been found on the Patent Rolls (P.R.O. C66/885 m. 9d.). The City of London did not have a separate Commission of Sewers until after the Great Fire; its Commissioners were always appointed by the Common Council and their powers were vested in that body by the City of London Sewers Act 1897 (Act 60 and 61 Vic. c.133)
On 21 May 1608 a Commission of Sewers was issued to Sir Nicholas Mosley 'maior of London' and others 'for Turnemyll Brooke and Fleets ditche in Lond. & Midd. and the Watercourse that runneth from Clerkenwell to holborne Bridge and soe into the Ryver of Thames'(Stow's Chronicle). Although this appears to be the first of the Holborn and Finsbury Commissions, the next covering this area appears to be that 'for the Cittie of London and two miles from the same' (1615) (Act 6 Hy. VI c.5) though this must have overlapped the area of the Westminster Commission. The later 17th century Commissions have the area of their jurisdiction described in similar terms and it is not until 1699 (Act 23 Hy. VIII c.5) that 'the Divisions of Holborne and Finsbury' are specifically mentioned.