It would depend on the context of the succession. If the successor was a spouse, there would not be a vacancy because that spouse would be immediately, automatically entitled to take on a future lifetime tenancy. If, for example, a child wanted to take over a tenancy, it would probably be short term. The only automatic right is with a spouse.
Housing and Planning Bill
Proceeding contribution from
Baroness Williams of Trafford
(Conservative)
in the House of Lords on Thursday, 10 March 2016.
It occurred during Committee of the Whole House (HL)
and
Debate on bills on Housing and Planning Bill.
Type
Proceeding contribution
Reference
769 c1498 
Session
2015-16
Chamber / Committee
House of Lords chamber
Librarians' tools
Timestamp
2016-04-13 16:37:31 +0100
URI
http://hansard.intranet.data.parliament.uk/Lords/2016-03-10/16031039000150
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