This is a female example of the Rabbit Hutch spider, Steatoda bipunctata.
This is the most common and widespread of our six UK False Widow species. The common name comes from their love of sheds and outbuildings, including rabbit hutches, and I doubt that there is a rabbit hutch or shed in the land that does not have this spider in residence.
It is a very common garden species throughout the UK and is not a species implicated in bites as other members of this group are.
For more False Widow information please see the flowing links:
Thank you very much for your reply.
I felt very sorry for it in its jar so have set it free (outside!)
What spider is this? Found on my outside window.
I have a 5 month and with all this false widow stuff going around I would rather make sure it's not one
Baird1604, yours is a Lace web spider, Amaurobius sp.
Several species of lace web spiders are common around the outside of our homes and gardens. They make a characteristic lace-like web on fences, sheds, walls and among general clutter around the garden.
Males are prone to wander indoors when mature and looking for a mate. Bites have been reported when a spider has been trapped against the skin, but with little pain or lasting symptoms.
You may come across the odd one in the house, particularly in very wet weather as they get washed out of their homes - but 4 month year olds are safe.