One needs to be BA Gold and travelling in F to gain access to the Concorde Lounge in T4. While I would agree that Terraces beats the First Class Lounge, if you can swing it the Concorde Lounge is the place to be. Last month I was travelling in F to BKK and checked in at Terraces, where I was informed that the First Class lounge was open to me. Upon arriving there, I was told that Concorde was okay.

Escaping the cacophony of Terraces on a Saturday night was amazing. I was served a full dinner before boarding my flight, and didn't have to elbow my way into the internet area (to check my points, of course!)