After five years of almost constant disappointment, I have found a place that not only has great burgers *for London* - but great burgers *for anywhere*.
It's called Gourmet Burger Kitchen (don't be put off by the name, the place is strictly utilitarian) and there's one in Clapham and one in West Hampstead.
It's run but Kiwis. The menu is pretty straightforward: a few topping options - including satay (yuck); blue cheese; mango & ginger salsa; aioli...I had the classic (plain and simple). The burgers are huge hunks of Angus beef, and come with lettuce, onion, tomato & relish. The buns are just right. The default option for burgers is 'medium' but I ordered mine rare and it was perfect.
They have milkshakes, fresh lemonade, freshsqueezed juices, soft drinks and a few wine & beer options. They also have chicken; chorizo and several vegetarian options, like a portobello "burger". Chips are huge and wonderful, served with aioli. No desserts though I wouldn't have had room.
At the one in West Hampstead (havne't been to the other) you order at the counter, and they bring the food to your seat. Seating can be communal. I saw lots of diners on their own, which I always think is a *good* sign i.e. that they feel comfortable enough to come in on their own. I am sure it's kid-friendly too, though most of the "kids" there on a Friday at 9PM were 'club kids' fueling up before a night on their feet.
The staff is very nice and efficient - there don't take reservations, and the queue was out the door, a situation that, I'm sorry to say, would have flustered most British staff so much that they would have closed the door and sent people away.
But everyone was patient and good-humoured. They also do take-away. Two burgers; two drinks; and a plate of chips cost £16 and we walked away stuffed.
If you're pining for a great burger in unpretentious, friendly surroundings, and don't want to have to pay through the nose...go!