I often take pictures of tap handles in order to easily help me recall both the breweries and the beers that I have sampled in a pub. Last year in the Brandy Cask, a brewpub in Pershore, Worcestershire, I took a picture of a row of cask ale tap handles with the landlord standing behind them. I was immediately accosted by the landlord for doing so.
I was sternly told by the landlord that it was illegal for me to take pictures inside his pub, and indeed, any pub in England without the permission of the landlord. I apologized and said I would remove the image from my camera if he so desired. He relented and said it was fine, just this once, though.
However, it must also be noted that you may take as many exterior pics as you wish without asking for permission.