The Inheritance Tax Return form (IHT205) is used to report the value of the estate and any Inheritance Tax due. The penalty for late filing of the IHT205 form can vary depending on the circumstances. If you file the form more than 3 months late, there is an initial penalty of £100. If you file more than 6 months late, there is an additional penalty of £10 per day for up to 90 days (up to a maximum of £900). If you file more than 12 months late, there can be additional penalties based on a percentage of the Inheritance Tax due. It's important to ensure that the IHT205 form is filed correctly and on time to avoid any penalties.