Perhaps the short answer to this question is that it seemed a good idea at the time!
Robert Dunning, the county and Abbey historian, was able to shed some light on Glastonbury’s elevated status and the early days of the corporation, at an event in the Town Hall on March 30 organized by Glastonbury Conservation Society to mark the town's Tercentenary.
By a charter sealed at Westminster on June 23 in 1705, Queen Anne granted the town corporate status, which remained in force until the Municipal Reform Act of 1834. Wells, Bridgwater and Bath had achieved borough status long before, but Glastonbury since the dissolution of the Abbey had been a backwater. Certainly, before that time the townsmen had through the various parish officers managed the affairs of their community. They even possessed a common seal, as well as property of their own.
The Abbey, however, retained a firm control of local affairs and the various courts that dealt with administration and disputes. Such centralized local authority vanished in the decades after the dissolution as both the physical and administrative aspects of the institution were plundered and erased. An attempt in 1554 to make Glastonbury Somerset’s county town came to nothing.
After nearly a century of religious and political turmoil in which the town found itself directly, if unwillingly, involved, a petition for a charter was made, largely on the grounds of better securing law, order and local justice. Instrumental in the success of the campaign was Peter King, a native of Exeter and a prominent Whig MP and lawyer. Why he should have had such interest in Glastonbury is a mystery, but it is possible that he saw the charter as a step toward creating a parliamentary borough that would return two MPs.
The corporation set up by the charter did not perhaps fulfil the desires of the petitioners. It created a Mayor, who could veto any proposed new member of the corporation and who usually presided at the petty and quarterly general sessions; a Recorder (the first being Peter King); a Town Clerk; eight Capital Burgesses and sixteen Inferior Burgesses. Nearly all the members of the corporation were gentry, landowners, lawyers or tradesmen and formed what in essence was an exclusive gentleman’s club: the body was a self-electing oligarchy with no popular mandate and no incentive to help anybody but themselves.
The corporation had no property and no corporate income, and indeed no real functions apart from peacekeeping. When they did stir themselves to action, it often rested on no legal authority.
Unfortunately the early records of the corporation are lost, but for notes made from them by a Mr Serel. Surviving records begin in 1786 but reveal little activity apart from internal elections. Their role began to increase as the century wore on, and as a result of their efforts, by somewhat questionable means, the present Town Hall was eventually constructed and completed in 1817 to replace the unsatisfactory Market House, which stood in the middle of Magdalene Street, in front of the present Town Hall.
As in so many fields, the Victorian era brought reform and the Glastonbury Corporation was duly modified in 1834 and at last began to undertake the tasks that perhaps the petitioners had hoped for back in 1705.