After we had a rat get into our kitchen while replacing some decking I bought a couple of these and it was the best £5 I’ve ever spent
https://www.toolstation.com/sure-set-rodent-trap/p24391.
They absolutely can’t resist peanut butter and take the bait in no time. Only once it didn’t crack the rats neck but got its head/face instead and I found it convulsing but it died in a couple of minutes so I don’t think it suffered much.