Hi John,
Please accept my sincere apologies for the delayed response to your email. We have had a huge number of enquiries in over the past few days!
We can confirm that this is actually a corn snake. This is bound to be an escapee. Don't worry, they are completely harmless and popular childrens pets. If the snake is still in your outbuilding it is best to contact the RSPCA. You can tell them that the snake has been positively identified.
Snakes don't need to eat regularly and it has found shade in your outbuilding so it should be ok for a period of time.
I hope this helps,
Best wishes,
Angela
Enquiries Service
Amphibian and Reptile Conservation