We have a vandal in our midst. Like a crafty little Banksy, someone in the Gallery has made use of the staff notice board, Google and some glue to strike terror into the very heart of the organisation.

It appeared quietly and without fuss the other day. The curators' little model of the exhibition spaces now contains a beautifully fashioned wee parody of the Thursday lunch-time pilates class. See if you can spot anyone you recognise.

The culprit's identity remains a poorly kept secret within the building. But feel free to have a guess... The winner wins the respect of their peers.