I can confirm also that you can smoke outside the terminal building at Birmingham airport, plus you can also smoke in departures etc at the side of the Meriden bar which opened last year. But to go outside you need to purchase the code, its key padded. The staff at the Meriden will give it to you. Its all under canopy and you have to stand, no seats.

Also East Midlands you can smoke on a balcony through departures as well .... at the side of a bar.

Beware though at Cancun airport you cannot smoke at all. Only outside, so leave it as long as you can because once inside and through that departure lounge you cannot go back.