I am working with a young person who my authority have PR for.  he is placed out of authority and has been for 7 years with independent foster carers who are great.  This young person is saying when he becomes older he wishes to stay in the area and with the carers.

Which authoirty is legally responsible for support and payment post being a looked after child as I am getting lots of conflicting messages and no one wants to pick up the bill.

the only experience I have of this is with a young person who was placed in residential care moving into the community.  In that case the placing authority remained responsible for them after the age of 18.  I suspect the situation is a bit more complicated for your young person and depends on a number of factors including whether your assessment is that they are best where they are eg to access specialist employment, education or social resources.  In such circumstances it could be argued that the placing authority should continue to pay for any care the person requires but you may have a bit of a battle ahead of you.