Off to Leopardstown races

The horse box was bounding along the road at about sixty miles an hour so it wasn't long before the police decided to investigate.

'You're not breaking the law, sir, but we're surprised how fast you're going with a horse box.'

'Well, you see, officer,' said Seamus, 'I've nothing aboard. I'm off to the Leopardstown races and I'm in charge of the non-runners!'