In reply to elsewhere:
• The NHS does not normally provide free hospital treatment for
people who do not reside in the UK even if they are UK nationals
• If you have lived outside the UK for more than 3 months
(6 months for some pensioners) in the last year you can be charged
• You will be exempt from charges if you can produce evidence that
you have been working abroad for less than 5 years and have lived
in the UK continuously for at least 10 years at some point
• If you are residing in another European Economic Area member
state you should show your European Health Insurance Card
from that country or apply for a Provisional Replacement
Certificate where possible
• If you have come to the UK from a non-EEA country that the UK
has no bilateral agreement with you will be expected to pay for
treatment unless another exemption applies to you