Possibly - Johnsons Blue.

Not sure of the leaf though.

definately Johnsons blue [cranesbill]

Isn't the clump rather neat for Johnson's blue - it tends to be a bit more lax than this, but perhaps its a new plant.

Might it be 'Brookside'?

Thanks Fractal Cat, Freesabird and Steragram.

It is a new plant which I bought from a stall, unlaballed and this is its first flower.

The colour is actually a little deeper than the photo shows with the veining and little pointy bits, on the petals, being almost violet/red.

It also has six petals...there is another bud coming, which has the little points...but, I don't know if the extra petal is just a little aberration?