The law governing the disposal of ashes is muddled. This is because, the Cremation Act, 1902, supposed that everyone would want to bury ashes after cremation. It did not envisage people wanting to scatter them.
Inasmuch as ashes do not constitute a health hazard, nor do they outrage public decency, you can do what you like with them. But if you bury them in a local authority-run cemetery and subsequently want to dig them up and move them, you may encounter difficulties.
Local Authorities Cemeteries Order 1977, which applies to local authority cemeteries, defines “burial” as including both “human remains” and “cremated human remains”. All interments are recorded in the burial register and there can only be an exhumation with a faculty or a licence. An exception, it seems, is Northern Ireland, where the recording of an ashes burial is at the discretion of the cemetery manager.
Local Authorities Cemeteries Order 1977 is consistent with the Burial Act 1857: “it shall not be lawful to remove any body, or the remains of any body, which may have been interred in any place of burial, without licence.”
What, then, constitutes an interment? In practice, if the buried ashes you want to dig up are in a container, constitute a ‘discernible mass’ and have been recorded in a burial register, you’ll need an Exhumation Licence or a Bishop’s Faculty. But if you’ve buried them in your garden you can dig them up as often as you like.
Whether or not ashes have the status of property remains untested.