Back track the trail to where it comes into your house and set a small dish of beer at the location. Slugs love the smell of beer, crawl up the side to investigate, fall into the beer and drown... voila empty them out in the morning and be alert for more since they never are alone...
We use the smallish white foam type picnic dishes which seems to work well. Best of luck!
this is what is funny the trail starts in the middle of the room,perhaps they dont leave a trail until they have sped up[lol] ill give the beer a go .thanks
On the odd occasion we have had slug trails downstairs we have waited until one of us has needed the loo in the night, then we also pop down stairs and catch the slug 'in the act'.