Isn't that the reference for the payment? You can set up a reference for payments you send out to people, usually for things like standing orders so you can write down what the money is for. Sounds like they've just put the asterisks there and no real description of what the money is for.
Right, back now and I have done some more digging. It's a Barclays account - when you expand the transaction it says something about it being 'pers OD tier 2 @£XX' (personal overdraft). It also has a little picture of a bank with an arrow point to it i.e. bank charge.
So it seems it is bank charges....they could have just written that in the bl00dy description!