The edge of a Pimlico housing estate, opposite some very smart-looking London townhouses, is an odd place for one of the UK's best-stocked craft beer pubs. This is the Cask Pub and Kitchen (or 'Cask' for short), a pub that's fast becoming a must-visit destination for the discerning beer enthusiast.
The range of beers on offer is simply staggering. With 10 cask ales and 10 imported keg beers on the bar, and more than 300 bottles to choose from, customers are advised to ask for the beer menu on arrival, to make sure they peruse the full range.
Deliveries come in almost daily, so stocking the selection can be a challenge. Some bottles are kept in fridges behind the bar, while there are more in fridges out the back and a small cellar. Overspill is kept in the little warehouse at the back of the pub, which is often two or three casks deep in beer. It's an impressive set-up, and the sort of place where you could spend an afternoon without really noticing the time pass by.
Greene King bought what was to become the Cask from Bass about 20 years ago. Various tenants had struggled to make it work. There were problems with drugs and violence, and a shooting in the doorway just a couple of years ago.
Back then, Westminster council regarded it as one of the worst pubs on its patch for problems, and was considering not renewing the premises licence.
So how did Martin turn the place around? Much of it, he says, is due to his past experience.
Before signing his current rolling lease at the Cask, he was a tenant with Punch Taverns at a pub on Chelsea Embankment. He admits it was a steep learning curve and he struggled to make the pub work over three years, but the experience gave him a huge amount of confidence. "Working on the tied model, offering the same beers and food as everyone else, was unsustainable," he says. "The pub struggled to make money, the recession came and it was not a good experience.
"With pubs in London, you either need to be cheap, or good."
Martin's arrangement with Greene King has been very different from his time with Punch. He's found their management to be more open-minded and forward-thinking, particularly his business relationship manager, Bob Luke. "There is a massive difference between Greene King, who make beer, and Punch - a property company who are purely after your rent. Greene King cares about pubs and beer," says Martin.
Just 18 months after opening, the Cask now attracts up to 300 people on otherwise quiet Monday nights for its 'meet the brewer' events. Recent participants have included Marble Beers, Dark Star and Lovibonds, while Hogswood and Coastal teamed up for a joint Cornish evening. Mighty Oak, Moor and the Bristol Beer Factory are all lined up to take part next year.
Martin wants to get the 'meet the brewer' nights to the stage where people trust the event, rather than the name of the brewer. He hopes that by opening people's minds to new beers, he might persuade them to spend a little more on a top craft beer brand such as Mikkeller - and with more than 30 varieties of the 'cuckoo brewer's' bottled beer on offer, this kind of customer education can only work in the Cask's favour.
Martin sees the 30 to 50-year-old market as the great beer generation, and they're not all CAMRA members. "Young people are interested in great beer and there's a sizeable market," he says. "You can go to a restaurant and pay £40 for a bottle of wine you can get in Oddbins for a tenner, but you can't buy the beer I sell in the shops."
While Martin is a self-taught beer enthusiast of some note, he's not into beer blogging, nor is he friendly on a personal basis with brewers. He buys beers directly from breweries, importing kegs and bottles from Belgium, the US and Germany in particular. Plus, he is annoyed by the tendency for marketing types to overuse the term 'premium' when it comes to foreign beers.
"Anyone who's travelled knows a mass-produced beer that's 10-a-penny in its domestic market is not a premium product just because it comes from far afield," he says. "You've got to justify the price."
Some of the beer he stocks is not to everyone's tastes: "The worst beer I ever sold was a beer with liquorice in. It didn't sell at all well and was fairly undrinkable. It would be unfair of me to name the brewer, but it's great that people are experimenting.
"People sometimes think that the Belgian lambic beers we serve in the pub are 'off'. Because they are brewed in open vats they are very sour, and people aren't used to them at first. If they really aren't happy, I'll change it. But often, after two, people get a taste for it, and appreciate it."
With more and more brewers offering 30-litre kegs of beer, which are disposable and offer excellent shelf life and quality, Martin doesn't have a problem with stocking kegs as well as casks.
"Keg and cask are both quality products. Cask is special for pubs and it shouldn't be lost, but it doesn't mean that stuff in kegs or bottles is rubbish. It's incredibly outdated to say so."
Martin is currently on the look-out for another site in London, possibly south of the river. Not with a view to starting a chain, just setting up another site that concentrates on beer quality.
"Small operations can go beyond what chains can offer and be ahead of the game," he says.
"The formula to a good pub is simple. Offer a different atmosphere which includes great beer, good conversation, soft music and quality fresh food. Leave Sky, quiz nights and additional events to your competition."
Martin's desert island beers
If you were to take one cask, one keg and one bottled beer with you to a desert island, which ones would you choose?
Cask
Dark Star Hophead - "A great session beer. It's a travesty that it's never won Champion Beer of Britain."
Keg
Great Divide Hercules Double IPA - "A powerful US IPA with a hefty backbone of nutty, malty sweetness that balances its aggressive hoppiness"
Bottle
Shmaltz Jewbelation Bar Mitzvah - "A kosher beer from the He'brew brewery in the States, which includes 13 malts and 13 different types of hops. The result is a lovely thick crude oil of a beer!"
• Next month, we visit the Euston Tap.