My wife is a UK General Practitioner, and this is what she has said after recent guidance distributed through
GP Update and
Hot Topics courses:
We are obligated to keep any identified overstayer on the premises and inform the local police in order for them to come and arrest that person.
However, she also says this:
We have no way to identify any person as an overstayer, unless they informed us.
The way medical systems currently work currently is that there is basically no central reporting system in place for instant access to statistics - this data is generally presented up the tree via audits submitted on request.
This is what she has to say about your individual questions:
is the provider going to make this information available to UKVI?
There is currently no guidance at the GP level as to who has what level of access to what data.
Would this include some very sensitive and personal information like their diagnosis and treatment.
Almost certainly not, given that diagnosis and treatment information is not accessible uniformly across the NHS currently - you can be a British citizen living in London and an A&E department in Manchester almost certainly won't have detailed information on you.
My wife also works for the local out of hours GP service, and they do not have access to patient records either.
The likelihood of UKVI having greater access to patient records than disparate portions of the NHS is low.
Automated data sharing within the NHS is a current goal of the government, but its a long long way from fruition. Automated data sharing between the NHS and external governmental bodies is currently non-existent and is likely to remain so, especially on the level you are asking about.
Would UKVI show up at the clinic to arrest a tourist who had overstayed?
Again, no current guidance has been issued on data sharing, but as mentioned, GPs are obligated to inform local police when they have a known immigration offender on premises.
What this basically boils down to in practice is the NHS is required to hold detailed and accurate billing information for overseas visitors - currently an overseas visitor can attend multiple NHS trusts for treatment essentially anonymously and not breach any billable limit.
This act defines a way to enforce the tracking of a single-identity for each overseas patient across multiple NHS Trusts - the
consistent identifier being an NHS patient number, which now carries the requirement of identification to be issued, so it will be linked to a passport or other travel document if the applicant is not a UK citizen.
Its worth noting that there is no current access for UKVI to patient information - the addition of a
consistent identifier does not grant UKVI access to this information.
But it could in future.