This is a moth, its called a Vapourer Moth (Orgyia antiqua), its a female. They are wingless, so under those eggs is the webbing and pupal case she matured in, she waited for a male to find her and then laid her eggs, she will die soon (the females only live a few days) and the eggs will hatch in spring and the caterpillars will go in search of food.
Thanks Crystal, brilliant answer, yes it certainly did help and wow you were quick off the mark too!
I replied useing email not realiseing i had to go through this channel hence this late responce!!!!
In early spring they hatch, so i presume they are ok in the cold! I'm curious now as to the catapiller that's going to emerge so apart from blankets and chucking a hot cup of tea at them when it's cold, leave to their own devices i guess!!
Really apreciate your answer, i live near Ludlow Shropshire for your reference