Can you keep a secret?

First you will have to buy it.
Each year the Old Lock-Up Gallery hosts a secret postcard exhibition which raises funds for the gallery but also donates to the charity Arts Emergency. All the postcards sell for the same price of £15 so they really are a bargain and Arts Emergency needs the support.

It opens on 21st August and details are on their website. Online it opens on Monday 23rd August.
I have donated one work to the show - see if you can guess which one it is.