Also, we would need to understand what the costs of administering this new system would be.
...because there would have to be a whole IT infrastructure put in place which would link NHS numbers to a production facility which would have to be set up with high level encryption algorythms in order to prevent fraud.
Basically, we'd be creating a system much like that used by the Passport Office.
Entirely feasible, but the cost of setting up, administering, policing and upgrading the system could cost far in excess of the amounts being lost to 'health tourism...which according to Fullfact.org, may be as low as £7million.
http://fullfact.org/factchecks/health_tourism_costs_nhs_reform-2805
Zeuhl - In the past the Daily Mail have quoted £200million, but this estimate was made in 2003 by debt collection agency CCI Legal Services, which works with the NHS to recover payments owed.
The £7million figure is a real 'write off' - where the NHS has given up on foreign debt.
The company CCI tried to estimate the cost of overseas patients that go undetected by the health service, and therefore claim free care for which they were not eligible. This came out to £50million to £200million.
The Mail (and other sources) chose to report the higher estimate.
Furthermore, these figures are now ten years old. And as FullFact.org has commented, there is greater awareness of this now, so that figure may be lower.