Notice anything? As the Gloucestershire countryside careens past, our view is compromised by a greasy residue on the windows. What could it be? The answer comes from our ticket inspector who tells us our carriage is often conjoined with the disco-carriage chartered by Welsh MEPs on the last leg of their Euro journey home from Euston to Cardiff. The residue builds up from the glycerine smoke machine, exactly the same residue that goes into the lungs of vapers. If you were to hold up x-rays of vapers’ lungs against the window its likely you wouldn’t get to see Swindon at all.