Normally any request to enter the United Kingdom must be made within a category within the Immigration Rules. However, it is possible to grant someone limited leave to enter the United Kingdom under the category of ‘Leave Outside the Rules’.
There are two circumstances in which “Leave Outside the Rules” will be considered in non-asylum and non-protection cases:
where someone qualifies under one of the immigration policy concessions; or
for reasons that are particularly compelling in circumstance.
There are currently 25 immigration policy concessions which are outlined in chapter 1, section 14 of the Immigration Directorate Instructions, which may be found at:
http://www.ind.homeoffice.gov.uk
Cases where there are particular compelling circumstances will be considered on their individual merits and in line with any relevant policy at that time. The decision to grant leave outside the rules in such cases will only follow in rare circumstances where there are genuinely compassionate and circumstantial reasons and no other option is available.