Simon F.
Yelp
So here's the hit; I moved to Brixton from Bangkok, so I am always on the lookout for authentic Thai food, that hasn't been Anglicised. I'm an intermediate - within reason - Thai speaker, and speaking Thai I find, helps get authenticity into your food.
Anyhow, to keep it short and to the point, Khao Sarn does the best som tam I've ever had outside of Thailand or Laos - an abundance of all the right flavours... a delicious explosion on the taste-buds. I've had it from here many times, and it's consistently near-perfect. The khao neow (sticky rice) is also as it should be, not too wet, not too dry. The laab gai was great, however not as spicy as it should've been - mai pen rai - we were given some home-made nam prik - a kind of chilli sauce - to add, and this fired it up as it should be. The tom yam goong didn't go down as well; it was a little salty and lacked depth of all the flavours normally present - although don't let this put you off ordering it - it may just not have been the day for tom yam. In conclusion, it seems the Isaan (northeastern Thai) food is where it's at, but I look forward to trying more dishes from other regions soon.
The prices are not expensive, nam plao is free, and it is a relaxed, informal Thai street-restaurant atmosphere, with an open kitchen and nice staff. You can even watch a lady pummelling your som tam ingredients in the giant pestle and mortar.
To summarise, from someone who moved from Pinklao, Bangkok, to Brixton, London - I would highly recommend you visit Khao Sarn, certainly for their som tam, which is truly, truly excellent. Just tell them you'd like it 'kon thai thammada'.