Council Tax Support is administered by your local council, so application deadlines and backdating rules can vary. You should apply as soon as you think you may qualify, because support may normally start from the application date rather than when your circumstances began. Some councils can backdate awards in limited situations, but this is not automatic and may require a specific request or evidence of a good reason for the delay. Check your council’s website or GOV.UK for the relevant application and backdating rules.