Tom Parker Bowles bacchanalia lunch at Blacks

Tequila is having a moment. Once the preserve of the Aztecs, who used to drink it an a digestif, the spirit fell spectacularly from grace, and until recently was more readily associated with cowboys, bandits and stag weekends than discerning drinkers. But with ultra premium brands like Patrón now on the market, Tequila has got the makeover it desperately deserves, and is not only cool again, but the fastest growing spirits category in the UK.

To toast Tequila's newfound success, I was invited to attend a Mexican-themed bacchanalian lunch whipped up by Tom Parker Bowles and Alberto Figueroa at Soho institution Blacks members club. Reached by descending a black steel staircase, the 18th century Georgian townhouse is modeled on the dining club created in the same spot 300 years prior by writer Samuel Johnson and painter Joshua Reynolds. Quintessentially English, Blacks is furnished with roaring fires, creaky wooden floorboards, powder blue walls, painted ladies, fraying armchairs and the odd ghost or two.

Taking my place by the roaring fire, a welcome Margarita is thrust in my hand. Noticing it contains no ice, I sheepishly ask the barman for a few cubes, to dilute the super strong concoction. Gesticulating wildly to my left is flame-haired one time Kenny Everett sidekick turned Tequila ambassador Cleo Rocos, who is so potty about the drink, she founded The Tequila Society to promote Tequila in the UK. To my right are Guardian food writer Matthew Fort and MasterChef winner and Wahaca founder Thomasina Miers, sporting a perfectly round bump.

Rescued from the fire before I begin to melt, we are ushered upstairs and asked to take our seats among the school-like wooden bench. On my table is Zeren Wilson of Bitten and Written fame, boy about town Ben Norum and Scotch eggspert David Constable. Foodie banter soon ensues. Having just been asked to be a food critic for the erotic review, Constable whips out his black notebook and begins writing sordid descriptions of our citrusy sea bream ceviche and crunchy tostadas served with lashings of luscious guacamole.

We all get in on the act and take to reading our lewd passages aloud. In need of slaking after our literary endeavours, we crack open a biodynamic Cortese from Piedmont producer Valli Unite. Golden in colour, it has a mineral core and a green fruited nose of apple and pear. After scandalously simple and pleasingly cheesy quesadillas, we move onto the main event, 'Drunken Lamb' – made tipsy by its beer marinade – served with fluffy tortillas and juicy black beans, and silky slow roast pork with Seville orange wrapped in banana leaves.

The highlight of the feast is raspberry red hibiscus and Tequila sorbet served in a modest glass goblet. Fresh, fruity and fun, the forest fruit flavours are lifted by the Tequila kick. Whilst savouring the sorbet, Tom PB emerges in a besmirched Tabasco apron and grey T-shirt. Humble as pie, he immediately defaults to thanking Figueroa, then scurries back downstairs. Catching up with him after the meal, I ask whether it's possible to do a quick video interview, but he concedes to having had one too many Tequilas to be sufficiently coherent for the camera. Disappointed, I ask him what he thinks should be served at the forthcoming royal wedding. "Cottage pie!" he exclaims. "I had it at my wedding and it's the ideal dish to serve to hundreds of people: it's simple, full of flavour and unmistakably British."

Tequila: don't slam it

When you hear the word Tequila what comes to mind – the worm at the bottom of the bottle? Hideous hangovers from one too many Tequila slammers? Whatever thoughts Tequila inspires, they are unlikely to live up to the refined recollections one associates with wine. Though the spirit has noble roots – Aztec royalty used to drink it as a digestif.

It was with interest and an open mind that I headed to Mexican mecca Café Pacifico in Covent Garden for a Tezón Tequila masterclass. Like Champagne or Cognac, Tequila takes its name from its appellation of origin; the town of Tequila. The spirit is made from the agave plant, which is not a cactus as is widely (and wrongly) thought. There are over 200 varieties of agave in Mexico, but only Blue Weber Agave is used in the production of Tequila.

Much like wine, Tequila production is strictly controlled, and the spirit can only be produced in five small regions around Guadalajara in northwest Mexico. The agave plant grows on volcanic soils rich in minerals and takes around 6-8 years to mature, depending on its terroir. Plants in the highlands mature more slowly than in the hotter lowlands, where the sugars ripen earlier.

A beautiful turquoise colour, the plants are cut and left to steam in a brick oven for 36 hours to help increase their sugar content. The juice is then squeezed out and placed in fermentation vats made of American oak, where yeast is added. The spirit is double distilled before bottling, or, in the case of the Reposados and Añejos, barrel ageing.

Like wine, flavour is obtained from the oak barrels and differs depending on the amount of time spent in cask. French oak imparts a chocolate aftertaste while American oak offers vanilla sweetness. Barrels can even be charred – old Bourbon barrels are becoming increasingly popular as they offer attractive sweet smokey aromas associated with Bourbon and Whisky.

There are two types of Tequila - 100% Agave Tequila (made solely from Blue Weber Agave) and Tequila, a blend that must contain at least 51% Blue Weber Agave. The final 49% can be a blend of sugarcane and corn sugar. 100% Agave Tequilas are considered superior to blended Tequilas, offering higher overall quality and purity of flavour.

Tequila is the fastest growing spirit in the UK, reflected by the emergence of The Tequila Society (www.thetequilasociety.co.uk), set up earlier this year by flame-haired comedy actress and TV producer Cleo Rocos to promote the category. Chatting to Rocos, she seemed keen to promote the spirit's slimming benefits: 'Mexican women use it to diet as it contains virtually no calories – I swear by it'.

I was advised to approach the Tequila tasting in the same way I would a wine tasting - first smelling the spirit, then giving it a swirl and allowing plenty of air in when tasting. First up was the straight-to-bottle Tezón 100% Agave Plata. As it has no contact with oak, the agave flavour really comes through, so you get lovely, gin-like herbal notes on the nose.

Moving onto the Reposado, the first thing you notice is the colour. A year in oak turns Tequila pale yellow. The nose was totally different to the Plata - with wonderful vanilla sweetness, charcoal and peaty aromas on display. The Añejo I tried was aged for two years in Bourbon barrels, giving it hints of maple and a lovely long smokey length. It was fascinating to compare the three, and witness the affects of barrel ageing. 

Last on the tasting menu was 'Diva', a pink Tequila soon to be shipped to the UK. Aged in Merlot barrels for eight months, giving it an attractive Provencal onion skin colour, the spirit was astonishingly wine-like. The nose showed fascinating Port-like flavours – raisins, prunes, sultanas, Christmas cake and chocolate, while the palate was smooth, full and feminine with a long peaty finish.

But what of the worm I hear you cry! You will never find a worm in a bottle of Tequila. They only appear in Mezcal, an almost identical spirit made from Agave potatorum. The addition of the worm has nothing to do with imparting flavour, it's more of a marketing ploy to show the spirit is strong enough to kill the worm. Producers pluck the worms from the agave plants and pop them (still wriggling) into the bottles.