If you are campaigning for or against a candidate at a combined authority mayoral election in England, you are covered by the rules for local campaigns.
The Electoral Commission does not regulate local campaigning. Complaints about possible breaches should be made to the police.
Under the local campaign rules, there are limits on how much you can spend on campaigning for or against particular candidates in a constituency or local electoral area. These limits are different, depending on the size of the electorate in the relevant area.
These spending limits cover spending on most campaign activities, including leaflets, meetings and digital campaigning.