For a connoisseur's cut of Canaletto, it's the Queen's Gallery

It's good to be king.

Particularly if it's the 18th century, you're young, rich, and your nation is becoming the most impressive global power since Ancient Rome. That was George III's situation when he decided to beef up the Hanover family art collection. His ancestors hadn't been keen on the stuff ... music was their thing ... but No. III was different. And by a magnificent piece of art historical serendipity, one of the age's great patrons was liquidating his mighty collection just as George started shopping.

The collector, Joseph Smith, had been British Consul in Venice for decades. A visit to his palazzo on the Grand Canal was a "must do" on every aristocrat's Grand Tour, and Smith made a tidy sideline of selling art to them while they were there. He hung his walls with local artists, particularly an exciting discovery of his by the name of Canaletto. The English milordi would order their own versions of what they liked at Smith's. Canaletto made a tidy sum. Smith took a commission. And, naturally, he kept all the best stuff for himself.

Which is why, despite fact that the National Gallery's 2010/11 Canaletto exhibition has barely faded from memory (review here), it's worth making an effort to see Canaletto & the Art of Venice at the Queen's Gallery in London. There is a lot of Canaletto strewn through the country houses and museums of the UK, but in purchasing Smith's originals, the royal family ended up with the best of the lot.

You'll also benefit from an atmosphere a lot less crowded than the National's blockbuster. Though it's been 15 years since the Queen's Gallery re-opened (after a major renovation that tripled its size and made it one of my favourite exhibition spaces in London) it still feels like one of the capital's great, undiscovered secrets. You'll be able to ramble around in here with plenty of open floor space to appreciate the art in quiet contemplation.

And these are works that deserve the time and attention. Canaletto was a master of detail. There's no better place to appreciate this than the early galleries of the show, which are primarily pen and ink drawings. Here, you can see the grid lines Canaletto used to build his perspective, and the obsessive way he'd study particular elements of a building ... down to noting specific colours he'd use later. Here's where we also first encounter some of the pastiches of ruins and buildings, both real and imagined, he'd sketch to stretch his imagination. This style of painting, known as a capriccio, has always been one of my favourites. It was a real delight to discover Canaletto's photographic style grafted onto these fantasy worlds.

You're really here, though, for just one room. The largest space at the back of the galleries is a riotous jewel box of Canaletto's best. On the left wall, the twelve scenes of the Grand Canal, covering sections from one and to another, that Smith hung in his house as the ultimate sales samples. I have seen many versions of these scenes, but never a complete set, hung together, in geographic order. On the opposite wall hang five spectacularly oversized canvasses of Roman ruins. I wasn't aware he'd ever tackled the subject. Forget Venice. I would have been ordering one of these! The other two walls offer more spectacular scenery, mostly Venetian, including a fascinating view of an alternative design for the Rialto bridge that lost out to the one we know today.

Other rooms show off the work of Canaletto's contemporaries. Smith's eye didn't falter. There's more luscious stuff here, from historical paintings and romantic landscapes to more architectural scenes and some exquisitely lifelike character heads done in chalk. You've probably never heard of Zuccarelli, Ricci, Carriera and the rest. If it weren't for Canaletto's enormous reputation, you probably would have. These works are worth your attention, too.

One of the glories of the Queen's Gallery is that a full-price admission is good for a year. Meaning you can pop back whenever you like to have another look. I'll certainly be doing so.

Canaletto & the Art of Venice runs until 12 November 2017.