After the election, the candidate must provide a written statement of their personal expenses to their agent within 21 days of the result being declared.1
The agent must meet deadlines for:
receiving and paying invoices
sending the candidate return to the local Returning Officer
Both the agent and the candidate must also submit declarations that the return is complete and accurate.2
You must still submit the return and declarations even if you haven’t spent any money.3
This is called a ‘nil return’.
You can find these deadlines, and more information on reporting, in After the election.