Bowing to pressure from a bipartisan coalition of community leaders, the Loudoun County Board of Supervisors reversed itself this week and agreed to a fall referendum on whether the board's chairman should be elected at large.

The unanimous vote took place Monday night, a time when board members had scheduled only an informal discussion of a zoning application and had planned no formal actions. The eight supervisors agreed to hold the formal meeting without notice.

The action came just three days after the bipartisan coalition began a petition drive to put the issue on the November ballot under state legislation sponsored this year by state Sen. Charles L. Waddell (D-Loudoun).

Currently, the Loudoun supervisors are elected to four-year terms from districts, and once a year they select a chairman from their ranks. The idea of creating a ninth board seat -- a chairman to be elected by the voters countywide -- has been suggested as a way to break deadlocks and foster greater leadership.

In June, the six Democrats and two Republicans on the board received a report from a commission it appointed to study the structure of Loudoun's government in which the at-large chairman was strongly endorsed. On July 17, the supervisors voted 6 to 2 against holding such a referendum, with the majority saying it had heard scant citizen support for the change.

Three days later, a group of prominent Democrats, Republicans, business leaders and other county residents calling themselves the Committee for Better Government announced the petition drive.

In a written statement discussing their turnaround on the issue, seven supervisors said they had been "impressed by the . . . citizen interest in this question" after their rejection of the referendum.