This small, cosy, not smoking restaurant is the best place you will find in London to taste Thai cusin. It will be hard to choose among the great selection of starters and main course, and you will want to come back soon to taste other dishes.
Staff is friendly and polite and the prices are ok.

Lemongrass may look like nothing much from the outside, but it's a top Thai restaurant and dead cheap. They don't just do pad thai either - there are loads of cool dishes to try and they do great fresh fruit for dessert.
Lemongrass is no smoking too, so you can really taste the food.