Applying for an EU citizenship while visiting UK

[kryn]

I am a British citizen and my wife is currently an Australian citizen to my knowledge she can visit me in the UK up to 6 months without a visa. She is entitled to a Portuguese citizenship as her mother is Portuguese(born there).
Wondering if it would be an issue for her to come to the UK to live with me as a visitor while she apply's to claim her Portuguese citizenship, to then possibly continue to live and then work in the UK after she receives it as she would be a legal citizen of the EU by hopefully the end of the permitted stay.
Both countries allow dual citizenship.

Is this legal at all, would there be any issues explaining this to border control etc?

We don't currently qualify for a spouse visa at the moment, so this is out of the question.

[Frontier Mole]

There is no issue doing what you suggest in principle.
The only issue might be at the point of entry to the UK. As a visitor she is expected to show ties to her home country and to return home. If you and her are obviously intending to reside in the UK you can see where the issues could be.

There is a risk attached to the plan but it is not an absolutely bonkers idea. It might be worthwhile making sure every item / document that she needs to apply for her Portuguese passport / citizenship is ready to be immediately applied for once you arrive in the UK. That in itself will not necessarily prevent entry if challenged but at least it sets out the intent.