Graves filled at least 75 years ago can now be re-used under new powers to ease pressure on London's cemeteries.
The re-used plots could accommodate up to six bodies
The plots can be deepened with room for up to six new coffins to be placed on top of the older remains.
Every effort must be made to contact any next of kin before remains are disturbed, the London Local Authorities Act 2007 states.
Ministers have said burial space in England and Wales will be full in 30 years unless changes are made.
Families could refuse permission for their ancestors' graves to be re-used for at least another generation.
But when the deeper graves have been re-used once, there will be no time constraints on when more bodies are buried in them.
The changes follow a 2004 government consultation which found most respondents were not opposed to re-using graves.
The powers are expected to be rolled out nationwide.