more commonly known as the Long Tailed Tit (for obvious reasons). The smallest of the Tit family, they generally move in flocks of 8 or more; just recently we've had either 1 or 2 come in to eat on the 'fat sausage' of which there isn't much left in this photo, hence the string which runs through the sausage and the remanents in the top and bottom are still there for the birds.
I adore these little chaps and they are possibly my favourite bird that visits the garden.