The date for a by-election in the Goldsmid ward in Hove has been announced.
Polls will take place in the area on Thursday, July 23, to decide who will replace Conservative Paul Lainchbury.
Mr Lainchbury resigned on Thursday for personal reasons.
He had faced criticism for missing meetings and community events.
A notice of election will be published on Monday, June 15, and nominations for candidates can be staged between then and a deadline on Friday, June 26.
The by-election is expected to be fiercely contested because it could change the balance of power at the council.
The Conservatives currently form the controlling administration. The resignation has left them with 25 seats but they are regularly supported by independent Jayne Bennett.
Labour has 13 seats, the Greens have 12 and the Lib Dems two.
Voting in the Goldsmid ward was close in the last council elections, with Mr Lainchbury and Ayas Fallon-Khan claiming two of the three seats for the Conservatives and Labour's Melanie Davis taking the third.
The Conservatives, Labour and Green Party have all spoken confidently of their chances.
The Conservatives yesterday announced party activist Andrew Wealls as their candidate. UKIP also revealed they would contest the seat and announced former Talk Sport radio presenter Mike Mendoza as their choice.
Labour have previously announced Lis Telcs as their candidate, the Green party has picked Alexandra Phillips and the Liberal Democrats have selected Lawrence Eke.