When a casual vacancy occurs, for example through death or resignation, the Local Authority must give public notice.

If the vacancy arises within 6 months of the date that that councillor's term of office expires, the election will be postponed until the next ordinary election (except where the total number of unfilled vacancies on the Council exceeds one third of the total membership of the Council).  When the "6 months rule" does not apply, the Returning Officer must hold an an election within 35 working days (7 weeks) from

• the date of a High Court declarationin that a vacancy exists; or
• the date a written request is submitted to the Proper Officer of the Authority by two local government electors for the area (area means the whole of the Local Authority area - not just the ward concerned).

Local Government Act 1972, sections 87 and 89 (1) – (3)

	Day
The ERO to hold an election date within 7 weeks (35 working days) of a request to fill a casual vacancy
Publication of Notice of Election 5 weeks in advance, excluding weekends and holidays	- 25
First day for submission of nomination papers	- 24
Submission of nomination papers: 12:00 hours	- 19
Publication of Nominations: 12:00 hours	- 17
Withdrawals: 12:00 hours	- 16
Appointing election agents: 12:00 hours	- 16
Change or cancel a postal vote or proxy appointment: 17:00 hours	- 11
Publish Notice of Poll: 23:59 hours	- 6
New postal & proxy votes: 17:00 hours	- 6
Counting agents & polling agents: 23:59 hours	- 5
Amend electoral register - clerical errors & court decisions	- 5
First day to issue replacement ballot papers If a postal voter has not received their postal ballot paper by the fourth day before election day, they may apply to the returning officer for a replacement ballot paper. (RPR 2001, Regulation 78)	- 3
Replace spoilt or lost postal ballot papers: 17:00 hours	- 1
Election Day    08:00 - 21:00 hours	0
Election expenses (+1 day if the Result is declared after midnight) 5 weeks including weekends and holidays	+ 35