Exhumations are generally rare and tend to be upsetting for the family involved. They can take a long time to arrange and are usually expensive. For these reasons, it is always best to consult with all the relatives before proceeding.
Exhumation of both buried and cremated remains need an Exhumation Licence. You can apply for an Exhumation Licence from:
The Ministry of Justice
Coroners & Burials Division - Exhumation Applications
102 Petty France
Telephone: 020 3334 6390