Housed in a listed building on Edinburgh’s grand shopping thoroughfare, Johnnie Walker Princes Street has a flamboyant presence to rival Edinburgh Castle, opposite. However, those in the know are drawn to an unmarked door down a narrow wynd at the side of the building. This is the entrance to private rooms not included on the general tour. It’s also the gateway to parent company Diageo’s world of the private client.

Upon entering The Apartment, guests are immediately surrounded by liquid goodies from the British drinks giant’s Rare & Exceptional portfolio: an emerald-green Johnnie Walker 48YO; 1994- and 1995-vintage Mortlach; bottles from the cult “ghost distilleries”, Brora and Port Ellen.

Private clients can enjoy the award-winning public tour, which combines theatrics, technology and cocktails in one entertaining and informative hour. But the hosts will also ensure privacy in the public spaces, whether closing the Explorer’s Bar for a mixology masterclass, or reserving the private dining room at the 1820 Rooftop Bar, which commands the building’s best views from the Castle to Leith. There is also an underground chamber of liquid secrets, rarely visited (and never photographed). Discretion is rewarded in the form of an expertly guided tasting.

The private client team can arrange accommodation at hard-to-access hotels such as the Gleneagles Townhouse. And connections mean access to unexpected attractions. Jewellers and silversmiths Hamilton & Inches, on George Street, has provided silver collars for Diageo decanters, and it’s well worth climbing the stairs to meet the craftspeople in their ateliers.

Edinburgh is only the beginning of the private client journey. Essentially, the whisky company has created a top-notch concierge service, or arguably the most prestigious tour operator in Scotland. You are spirited away to your choice of distilleries in all corners of Scotland. Many visitor experiences have been revamped as luxurious “brand homes” – most recently, the Singleton of Glen Ord on the Black Isle, Caol Ila on Islay and Talisker on Skye. Others are traditional favourites such as Lagavulin (also on Islay).

Even less explored brands have excellent private client spaces and offer samples such as the annual Prima & Ultima Collection of one-offs and last drops. Cardhu’s VIP space, for example, looks across rolling Speyside countryside from one window and, from the other, into a warehouse full of casks from different distilleries.

Along the way, guests might stay at the Fife Arms in Speyside, Newhall Mains on the Black Isle, Links House in Dornoch, or even Skibo Castle. Activities – field sports, falconry at Dunrobin Castle, climbing and hiking – can be arranged.

The highlights, though, are private tours, such as at the in-demand reopened Brora. Rebuilt almost brick for brick, it looks stunning. Glide past the crowds at neighbouring Clynelish to its gates with their wildcat logo, and beyond is peace and quiet (until you reach the stills). It’s a geek’s delight – you even get to “work”, for example, taking samples of the wort to test the specific gravity. Then to lunch – by the chef from Links House – in the Brora Dining Room, accompanied by a sampling of The Triptych. The original Brora produced different styles in different eras. In the new era, it is trying to reproduce each of those phases – but it will be decades before those liquids eclipse the trio of 1972, 1977 and 1982 whiskies in this £30,000 set.

Further south, another “ultimate destination” is Royal Lochnagar, a mile from Balmoral. Here, the most aspirational of Diageo’s collectible whiskies are stored – the handful of Casks of Distinction, selected from Diageo’s stock of over 10 million barrels.

Global private client director, James Mackay, explains why these are so special. ‘Even a single malt is created by bringing together different casks from the same distillery to achieve balance. A single cask must be perfect by, as it were, act of God, rather than act of whisky maker. That is why these are literally one in a million. It takes 4,000 working hours a year to identify them.’

Casks of Distinction is aimed at collectors and connoisseurs, not investors. They are usually at least 25 years old and priced at the equivalent bottle value (from six figures to upwards of £1m). Purchasers commit to bottling the whisky after a maximum of five years, in which time they are welcome to bring guests to sample their cask. ‘That experience is a major motivator,’ says Mackay.

Casks of Distinction owners are a small percentage of Diageo’s private clientele; regular purchasers of Prima & Ultima (£45,580) and other Rare & Exceptional releases may find themselves invited to enjoy this hospitality. Mackay is reluctant to talk about minimum spend: ‘We make judgement calls about the likelihood of an ongoing relationship. We are keen to open the door to someone starting out on the journey to becoming a serious collector. Experiencing Scotland like this usually sparks a lifelong passion.’

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