Last Viking,
sorry forgot to include UKBA links.

Please look here:-
Especially SET7.8 "What is sole responsibility"
http://www.ukvisas.gov.uk/en/ecg/settlement/children

Also look here:-
Annex M - Children - Guidance - General
http://www.ukba.homeoffice.gov.uk/si...tion5a/annex-m

And here:-
Immigration Rules - Children
http://www.ukba.homeoffice.gov.uk/po...art8/children/