I’m talking to Amy, an O2 sales assistant, about the kind of person who comes in after a OnePlus phone: “They come in and they know exactly what they want – they just ask if it’s in stock, literally.”

The question is topical, as Amy is currently preparing to deal with a queue of a few hundred OnePlus enthusiasts, keen to get their hands on the newest member of the OnePlus smartphone family: the 3T. The OnePlus 3T improves on the previous model in three significant ways: it has a Qualcomm Snapdragon 821 processor, a bigger battery with Dash Charging (which offers “a day’s power in half an hour”) and a hugely improved front-facing selfie camera – it’s up to 16 megapixels from the previous eight.

As if the queue around the block wasn’t evidence enough, Amy tells me that there’s definitely “more of a buzz” for the new handset. “More people have come in and asked about it,” she tells me.

I initially thought that some people would have done the usual British thing and, seeing a queue, promptly just joined it, but in fact all the people in the queue knew exactly what they were there for. For some, it was to be their first OnePlus handset. Others were veterans of two or more handsets from a manufacturer that has disrupted the market by providing top-of-the-line, premium quality smartphones at a great price.

Their reasons for waiting up to three hours in the queue echo the reasons that the OnePlus 3 is currently top of our “best smartphones list”: its combination of top-of-the-line components and an attractive price. A woman a little further back in the queue is still clutching the original OnePlus phone – she tells me she’s really looking forward to seeing three years worth of camera improvements. For a man near the back of the queue, the convenience of a phone that holds two SIM cards at once will make life a lot easier (he’s holding an iPhone in each hand).

As a rule of thumb, the closer to the front of the queue I got, the more hardcore the OnePlus fandom. “I’ve come from Portsmouth,” a particularly friendly man tells me. “I’ve had a two-hour train journey – first time in London, using the underground – first time on Oxford Street!” Being a OnePlus fan, he’d seen the previous long queues for OnePlus pop-ups and thought it safest to come nice and early. Three hours in the queue, at the time of my interview, so he certainly got a good long look at Oxford Street.

“This will be my third OnePlus phone,” he continues. “I’m a big Android enthusiast, a big mobile phone enthusiast – I just love gadgets! I haven’t played with the OnePlus 3 so this is like a brand new phone for me. I’m really looking forward to it.”

At 3:02, he gets his wish. Or rather, the people at the very front of the queue do, as the queue starts snaking into the store and free t-shirts are handed out. The man at the very front of the queue – Alex, from Oxford – heads to the counter to purchase the first OnePlus 3T in the UK: 128GB in gunmetal grey, since you ask. He’s overwhelmed with joy when the price he’s all set to pay is waived as a thank you for being a super-loyal fan.

He’s definitely a worthy winner, having shown enormous brand loyalty. Alex owned the original OnePlus, then the OnePlus 2, then the OnePlus X that went to his wife when she bought him a OnePlus 3. “We’re a OnePlus family,” he quips.

The OnePlus 3T is on sale now at O2 and OnePlus.net priced from £399 for the 64GB model and £439 for the 128GB version.