Mei Ume at the Four Seasons, Tower Hill

Mei Ume is a Chinese and Japanese restaurant and not, they are at pains to point out, a Chinese-Japanese restaurant. There's no pan-Asian stir-frys, no Sino-Japanese fusion food, no crab & sweetcorn ramen or crispy duck sushi. Instead, Chinese and Japanese dishes sit alongside each other, not in separate sections of the menu but listed within similar categories, so you get, for example, prawn crackers listed right next to edamame beans in the snacks, and "Stir fried lobster tail with ginger and spring onion" next to "Wagyu beef teppanyaki with ponzu and miso dressing" in the Signature section. It's a conceit that still may have purists thinking twice, especially in these days of ultra-regional specialisation in Chinese and Japanese food, and you'd be forgiven for questioning whether the same kitchen could - or even should - be attempting all this at once.

At least, until you eat the food in question, at which point all of these questions of authenticity immediately fade into insignificance. Because whether you stick to the Chinese dishes or order only Japanese, or concoct yourself a weird geographically confused combination of the both (as we ended up doing), you're very likely to enjoy every last bit of your dinner at Mei Ume. The reason is in no small part due to an innovative dual-head-chef system, with one person experienced in the Cantonese traditions, and a sushi master trained in Japan overseeing that side of things. All of the dishes therefore have that all-important chime of authenticity, despite the two cuisines existing on the same menu.

And they've also got themselves a very competent cocktail person, based on these welcome drinks - a Sakura Spritz made with gin, cherry and yuzu juice, and a Geisha Martini, dry and perfumed with an elegent hint of sansho pepper.

It's surely the case that the best way of enjoying sushi - proper, high-end sushi - is to sit down at the bar at somewhere like Cubé or Tetsu and ask for omakase. There's something immediate and charming about having your food prepared in front of your very eyes, and having such control over the experience as a customer - deciding whether to have a second round of sashimi before moving on to the nigiri, for example - is empowering and actually quite thrilling. That said, given the limitations of the standard dining room format at Mei Ume, their sushi offering is astonishingly good. Sashimi of the finest otoro (meat from the belly of the tuna, rich with fat) and blindingly fresh, buttery mackerel were served prettily arranged alongside wonderful soft eel, sea-spritzed uni (sea urchin) and aburi (blowtorched) salmon nigiri, each boasting absolutely unimpeachable, body temperature rice. Only a rather sad pile of fake wasabi - coloured horseradish, as opposed to the real wasabi root which they really should be offering at this price point - let the side down slightly.

We let Mei Ume decide in which order to bring the rather eclectic set of items we'd ordered, and so next to arrive was their signature Peking duck, as deeply bronzed (and no less attractive) as George Hamilton, fanned out beneath a dainty clump of cabbage and herbs. It arrived alongside the familiar array of Peking duck kit - pancakes in a steamer, julienned cucumber and spring onion, hoi sin sauce - but also a bowl of plum jam, which was a nice touch. Really, though, this was all about the duck - and my God, what duck. That gorgeous skin, as delicate as the finest French pastry, rested on a layer of fat which dissolved in the mouth into rich duck soup, and left you to marvel at the texture of the flesh, just blushed pink (though by no means rare - the Chinese seldom serve duck rare), soft and yielding but with just enough of a chew to bring a smile to the face. I made a pancake out of a couple of slices as I was expected to do, but very soon ended up eating the duck on its own, to be able to simply marvel at it without the distraction of vegetables and sauces. I've had a few Peking ducks in my time, but this was an absolute world-beater.

If the rest of the evening paled in comparison somwhat to That Duck, well, that's hardly much of a criticism. Kung Pao chicken had an elegant set of flavours, with sweetness, sourness and chilli heat in perfect balance, and macadamia nuts added a nice bit of crunch. The chicken itself was perhaps very slightly on the dry side, but with so much else to enjoy it didn't matter too much.

Gai lan was perfectly cooked, with a great crunch and seasoned well by a silky ginger sauce. There's only so much to say about a plate of gai lan, but as plates of gai lan go, this was a good one.

And finally green beans with minced pork, the use of Iberico pig adding an extra depth to this classic dish. Very nice indeed, vibrantly flavoured and extremely enjoyable, but to be honest I was still thinking about That Duck.

As should be apparent by now, judging solely by the quality of the food offered, there is very little to criticise about Mei Ume. Hopping between Japanese and Chinese food from one course to the next has the potential to turn into a car crash, but by virtue of everything being done to such a high standard, and with each cuisine treated with such skill and respect, it all comes together marvellously. Service is attentive and knowledgable, and it's a beautiful room to enjoy it all in - the hotel (the Four Seasons) is the ex headquarters of the Port of London Authority, and is all high ceilings and Beaux Arts architectural flourishes, accented with Japanese and Chinese murals and details.

But there is the little matter of the cost. I was invited to Mei Ume, and though I'm sure I'd have appreciated the food just as much if I was covering it myself, the bill in question would have come to £261.56 (assuming 12.5% service) for two, not an every day expense. But you know what, £130 per person for a table in a five star hotel, plenty of booze, some of the finest sushi in town and the best Peking duck in the whole bloody world (probably) is most certainly not an unreasonable amount of money, and if you were in the mood (and budget) for a celebration, I imagine this would suit pretty well. Plus, they do a Saturday lunch menu for £25 which includes a glass of sparkling sake, and though it doesn't feature any of the pricier bits of sushi, you do get some salmon & avocado hosomaki (with that same fantastic rice) and some dim sum, so you can experience the whole Chinese-Japanese dichotomy in the same lovely surroundings for the price of an IMAX cinema ticket.

Not a fusion restaurant, then, but really two restaurants from two different corners of the world that happen to occupy the same few hundred square feet of hotel, Mei Ume is somehow not the confusion the concept threatens to be, but is in fact a remarkably versatile operation. You could settle in for a Cantonese feast, construct yourself an omakase-style sushi experience, spend a week's wages on dinner or lunch on a budget, and whatever you end up with is likely to be at least worth the money you pay for it. Which is by no means a given in five star London hotels, let me tell you. I would happily go back, and pay. Anything to have another go at That Duck.

8/10

I was invited to Mei Ume and didn't pay