I am a UK state pensioner living in canada with Dual citizenship. will the NHS cover me during my 3 week trip to the UK starting 22 June? I will travel with my Canadian passport
As discussed in answer to your other question, the The NHS is a residence-based healthcare system. As such, if you're not resident in the UK, you wouldn't normally have access to the NHS.
There is one other key exemption to the rules
So you're actually covered!
However, because you're not by default covered as a Canadian resident, you can't just turn up with a Canadian passport, nor an expired UK passport. You'll need to provide proof that you're both a UK state pensioner, and that you're ordinarily resident outside of the EEA.
The implementing the overseas visitors hospital charging regulations PDF covers your case in section 23(a), which gives:
So, you'll need to bring with you something that proves you live in Canada, and something from the DWP that confirms you're in receipt of a UK state pension. Also, plan to have to fill out some forms to go with these, so allow a bit of extra time whenever you want to deal with the NHS
It doesn't matter what passport you travel on, the answer is No! "If you are moving abroad on a permanent basis, you will no longer be entitled to medical treatment under normal NHS rules. This is because the NHS is a residence-based healthcare system." NHS
You should take out travel insurance.