I have dual citizenship Canadian and British. I receive a British old age pension. Can I use the NHS free when spending 2 weeks holiday in UK and Spain?
Yes you can, at least in Britain
Ordinarily eligibility for free healthcare in the UK, like most places, is based on residency, not citizenship, and being a British Citizen does not matter. However it turns out that there is an exemption for those in receipt of a British state pension.
If one of the following applies to you then you will be exempt from charges for treatment if it becomes necessary during your stay and cannot wait until your return home. This includes any pre-existing conditions that doctors say need prompt treatment while here. Any pre-planned or routine treatment will not be free
The applicable condition is:
Anyone receiving a UK state pension if they have lived legally in the UK for 10 continuous years or more at some point. This also covers their spouse, civil partner or child under 16 if they are travelling with them
Other exemptions include EEA residents, and those living in countries outside the EEA which have a reciprocal healthcare agreement.
If your pension is "a UK state retirement pension or another state benefit," and if you "have lived lawfully in the UK for at least ten years continuously in the past, or worked for the UK government for at least ten years continuously," then you are eligible for free NHS care.
Couple of points to clarify. If by NHS you mean the British National Health Service, then you can only use the NHS in the UK. When you are in Spain, you will have to use the Spanish Healthcare Service. If you are a UK citizen then you get automatic health insurance through your European Health Insurance Card (EHIC). This means that you will get the same treatment anywhere in the EU as you would in the UK. Now, what is actually covered by your insurance depends on your plan.
That said, emergency medical treatment will most likely be guaranteed. See gov.uk for more information.