Edward S.
Yelp
St John's Tavern is a High Barnet-branch favourite that, along with The Junction Tavern down the road, has both the food and pedigree to legitimately call itself a gastropub. (Not that it does, of course. Gastropubs, sort of like hipsters, have the property that the most authentic examples are the least likely to use the label on themselves, and the least genuine are most likely to loudly embrace it.)
Dinner and Sunday lunch are served in a dining hall that's decorated with competent charcoal and pastel portraits next to photographs of the pub and surrounding area, and it has a very distinguished cracked-and-repainted vaulted ceiling. So if you can, try to make a reservation in the dining room. Table 17 in the corner has a good view of the punters, and there are also big brown leather booths for parties: furniture hybrids of American diner crossed with Gentlemen's club (as in Garrick or Lansdowne, not Stringfellows.)
You can also show up and eat in the bar, but it's very hard to get a table there during the 7pm to 9pm after-office-hours crush. I don't think they take reservations for the bar area.
Whenever I have visitors they are brought, as a matter of course on their first visit to London, to St John's Tavern. Especially so if they are from the US and have made clever comments demonstrating their prejudice against British cooking. The food is indeed robust and practical, and it definitely follows the meat plus vegetable plus additional vegetable pattern, but is also heaped with modern style and flavour (their influences are on display in a small library of cookbooks at the back of the dining room.) It couldn't be further from a the sort of gravy soaked Dickensian chop house I'm sure most outsiders imagine les rosbifs Brits frequent. Pork chops, sausages and steak are on the menu, but so is olive tapernade, polenta and salsa verde.
Also of note: there is always a very good selection of seafood. Cornish rock oysters are a staple, as are the fish and chips -- haddock or coley, rather than cod -- and this was the first restaurant where I had a pea puree, which is more exciting an event than it sounds. Another classic is the mussels with chilli and chorizo, which makes a good light supper on its own if you have it with a side of the house sourdough and two pints of bitter. In both the restaurant and bar you can also get cockles, fresh anchovies, whitebait, and other snacks.
Menus are on chalkboards on the walls -- an single enormous one in the dining room -- and are written in a pretty chalk hand. At the back, over the kitchen, is a provenance board listing the kitchen's suppliers and another board listing the pudding menu. You should leave room for a pudding. I would recommend the caramel cheesecake with a glass of PX sherry.
Something that went hand-in-hand with the ascent of gastropubs was the giant scotch egg and St John's Tavern is a very good example if you're in the bar. They also have delicious giant pork scratchings. Don't be put off if your only experience of scratchings is of Mr Porky's meat industry by-products.
I've been eating and drinking here for over ten years now. Getting home used to take ten minutes on a 134 bus. Then I moved and it meant a cab ride to the other side of Hampstead Heath. For a few years I could only get here by 747, and now it's a cab ride through two boroughs. I hope to always keep coming back to this old friend.