A beautiful cat like that will have a owner that is probably worried, take it to a vet a really good one I use for my 2 pets in catford called all pets they can scan the cat and call the owners.
2 months ago we had a similar story but the cat was injured I took picture of it and knocked on every door in our street never found the owner was about to take it to the vets when it went off and came back next day all healed up and a collar. so it found its way back.
good luck