What did the OP do wrong here?

[applejuice123]

Referring to this thread, I would just comment on it but it's locked:

british-citizenship/sru-revocation-of-b ... 87178.html

Basically can someone explain what the OP of the above thread did wrong? I thought British citizens are allowed to travel on non British passports since the UK accepts dual citizenship? What does Zimba mean by 'Home office in the last few years has taken a hard stance against the abuse of british citizenship by dual nationals'?

[secret.simon]

Naturalisation has a future intentions requirement; that the applicant intend to reside and have their principal home in the UK.

The OP of that thread left the UK almost immediately after being naturalised, which gave rise to a suspicion that they may have been not completely honest about their future intentions at the time of application.

Complicating the picture was that they did not have a British passport to return to the UK. Their ILR became invalid when they became a British citizen. As a dual British/visa national, they could not board a flight back to the UK without a British passport (and Emergency Travel Documents are only issued to people who have already been issued with their first British passport). So effectively they were locked out of the UK without a British passport in hand. And when they applied for their first British passport from abroad, that raised the suspicion mentioned in the previous paragraph.

Based on that thread, we recommend that at the very least, newly naturalised citizens should apply for their first British citizen passport within the UK, get it and then travel abroad.

The issue with the OP in that thread was not that they travelled abroad on a foreign passport but that they did so immediately after their naturalisation. That latter bit was unwise.

[kamoe]

I thought British citizens are allowed to travel on non British passports since the UK accepts dual citizenship?

The UK allows dual citizenship. That doesn't mean they have the obligation to treat dual nationals as British citizens when traveling on a foreign passport and without no other proof of British citizenship. That's what a British passport is there for: to have the right to be treated as a British citizen. As a general rule, the passport you travel on is the citizenship you will be treated as, and the onus is on individuals to make sure they have the appropriate travel documents.

To travel on a foreign passport and expect to be treated as British, while not having any other proof of British citizenship, is unwise.

[Irenejg]

This has me worried. I posted another thread where the advice was that it's probably fine for me to travel on my New Zealand passport interview month or two right after my ceremony. What I didn't think to ask about was spending extended time away. My planned timeline is:
Ceremony - Jan 2023
Short term travel - Feb + Mar 2023 (separate trips, weekend length)
Longer term travel - 1 year in New Zealand April 2023 ~ April 2024
Return to UK ~April 2024

My plan was to apply for my British passport in New Zealand. But now I'm worried this will be a problem - like the other thread OP I will have moved abroad soon after naturalisation and will be applying for my first British passport from abroad.

[secret.simon]

it's probably fine for me to travel on my New Zealand passport

That should be fine as New Zealand passport holders are not visa nationals and so the airline will allow you to board a flight back to the UK even without a British passport or visa. Then, at the UK airport, you can speak to the Immigration Officers and explain your situation. There will be a delay, perhaps even of a few hours, on the return at the airport as the Border Force verify your details, but you will be allowed in.

The issue with the OP in the thread linked to in the opening post was that the recently naturalised citizen was a visa national and in a situation where the airline would not let him board without a British passport or a visa. And British citizens can't be issued visas. So he could not get to the Border Force at the UK airport to speak with them.

My plan was to apply for my British passport in New Zealand.

That bit is the bad idea. I would suggest staying in the UK in between your trips for a sufficient period of time until you get your first British passport. You can then take a longer sojourn abroad.