"There's a lot of people vying to be in the top three and they've got to take these products incredibly seriously. It's an amazing line-up backed by the most enormous research and development."
With no vested interest in seeing Huawei displace a Sony, an LG or a BlackBerry, Dunstone adds: "If you were anyone else, you should be scared."
Yu himself doesn't appear scared of anybody - he talks freely not only about Huawei's line-up, but also about the complex politics that have at times threatened to engulf the company. There could be no more palpable demonstration that secretive Huawei is trying, admittedly slowly, to open up.
When he sees a Samsung Galaxy S4 on the desk, Yu is blunt: "We want to provide the best, most beautiful, slimmest smartphone - this one's much thicker." Picking up on criticisms about the Samsung build quality he says simply: "We're not made of plastic."
Huawei claims Samsung - the biggest smartphone maker in the world - has built its success on hyperbole and enormous advertising spend. "In the high tier, if you have huge money to spend on marketing and branding, like Samsung, then everyone will buy that," he says.
"We don't have so much money to do marketing and branding so we have to make our products better. The best smartphone in the past was from Nokia, then from Apple, then from Samsung. And who is No1? The industry is so dynamic - no matter how successful you are, if you're currently No1, doesn't mean tomorrow you'll be No1.
"Samsung, they have such huge money - if you invest in marketing and branding then people will always buy no matter how good the products are.
"The Samsung Galaxy S4 is just a so-so smartphone."
While it's Samsung that has all the momentum, it's Apple that has set the pace for "cool" - the factor Huawei badly needs if it is to truly compete.
Never lacking in ambition, Yu thinks he's got Apple in his sights as well.
"In its latest update, Apple makes the phone extremely simple to use," he says. "But if we are just learning from them we can't catch up, because they are now slipping. We want to go higher than them."
Being "higher than Apple" is part of the thinking behind the software Huawei is using for the new phone.
A simplified version of Android, it also offers highly customisable interfaces, including a way to make the switch from one homescreen to another look like a windmill.
"We have a good relationship with Google," says Yu. "We want Android to be more user friendly, so we have made a lot of enhancements. Google is good for an engineer but it's not good for the consumer. It's a little bit too complicated."
Huawei will also go after new markets: "We want to bring a lot of personalised things - ladies like a lot of these things, so we're making it more suitable for them."
Indeed, Huawei's approach in China has been to build phones tailored for every market. Huge investment in research and development means that there is a phone, tablet or in-between smartphone "phablet" at a range of prices and a host of sizes.
The new P6 does represent a step change in the quality of its design and Huawei's clear commitment to a new approach. Hardly two years ago it had never made a phone in its own name, while the P6, up against Apple, Samsung and others already has 2 million Chinese pre-orders.
Yu says that in China, Apple is hamstrung by its lack of a large-screen phone. "Large-screen phones do very well in China," he says. "Asian people prefer large phones. Gentlemen can't put an iPad Mini in a pocket."
Moving on from the battle over products, Huawei is also involved in a battle over politics. Around the world it has had to deal with rumbling accusations that its network business could be used as a conduit for Chinese espionage.
In its defence, the company points out that it merely sells networking equipment to businesses which operate them.
Why would Vodafone, for example, put up with a back door that could be infiltrated by a foreign power? And, anyway, Huawei is a privately held company, not a state-owned entity.
These arguments appear to carry little weight with some politicians, as the United States and Australia restrict Huawei's operations in their countries.
In Britain, Science Minister David Willetts and Chancellor George Osborne have gone out of their way to welcome the firm and its significant investment.
"Consumers welcome the Huawei brand," says Yu.
"It's a [US] Government guy, a political guy [who doesn't]. Consumers like Huawei, and feel that we're a trustworthy brand, a reliable company.
"Politicians feel that Huawei headquarters are in China and China is the Communist Party and some governments don't like the Communist Party or socialist countries.
"Actually, China is not a socialist country any more, we're a capitalist country. The only difference is, we have only one party. Some leaders don't like this system. We are a Chinese company - if we were a British company, a German company, we'd have no problem."
Yu describes Huawei as "a globalised company, headquartered in China".
While many British companies outsource work to China or to India, Yu says Huawei is so active in Britain because it wants to recruit quality staff who can only be found there. This month the company opened a new British headquarters in Reading.
"The UK's a good [test bed] for America and the world," he says. "We hire a lot of UK people and we contribute a lot to society. In the UK we can get good people. We behave like a local company."
As Chinese companies, across Africa in particular, are accused of parachuting in their own employees without benefiting the wider society, in Britain at least Huawei is keen to stress that it is learning how to be a good corporate citizen.
None of this will placate the company's critics, but Huawei is a brand with bulk and ambition. "All retailers say they will buy more from Huawei," says Yu.
And retailers such as Dunstone certainly seem to agree. At the Roundhouse, he took to the stage to emphasise how good his own relationship was with Huawei, and how much faith he has in the business. But more than that, he implied it was time for a change in the established smartphone hierarchy.
"Typically over time the prices of the established products come down," Dunstone said later. "But, in fact, over the last five years the price of products has gone up as more features were added.
"Huawei understands as they build their market share they've got to develop a point of difference. And every one of my customers would like to spend less.
"Huawei is approaching it in a smart way - they're saying, 'How do I give people a better product at a better price?'. That's a lot more credible than the people I meet who say they've got a phone just like the iPhone but it's more expensive."
For now, Dunstone's Carphone Warehouse markets a Huawei device as "the best smartphone you've never heard of".
"There's a story round that," he says. "And you can demonstrate to people you're getting more for your money."
But he clearly thinks that story is beginning to change. The comparison he makes is stark.
"Ten years ago, No1 was Nokia. Just think how quickly you can be displaced."
Yu certainly agrees.
Huawei's rise
• 1988: Company founded by former military officer Ren Zhengfei
• US$4.7b: Research & development spending, 2012
• US$2.5b: Unaudited net profit, 2012
• 6.18mm: Thickness of the Ascend P6, the world's thinnest phone
• 2 million: Pre-orders for the Ascend P6 in China alone
• 140,000: Number of Huawei employees worldwide
• 2012: Huawei overtakes Ericsson to become the world's largest maker of telecommunications equipment
