One of the euphorbias. Looks like quite a nice one with the contrast of red and green.
Euphorbias are toxic (to varying degrees) and the sap is irritant so not particularly good if you have young children exploring the garden (though it does help to teach them not to touch!)

Thank you Urbanite I don't know where it came from might be birds but I have been round the garden and there are three of the them will pot two up and leave the other, I went on a euphorbia site and it looks like blackbird! thanks again Trevor Lawrence Nottingham

If you break a stem be very careful not to get any in your eye as it is caustic and extremely irritant. Its a useful little plant for a dry place especially in shade.