Always drive in reverse when you're drunk (True story)?

This is a true story. Many many years ago, before drink driving laws were as strong as they are today, a friend of my Dads, lets call him Dave, was leaving the pub, keys in hand and a hefty number of pints on board.

"Jesus, am I all right to drive" he wonders as he misses the ignition with the keys for the third time. "Sure I'll be grand. Right onwards and sidewards" and off into the night he trundles.

He gets on the motorway, desperately trying to keep things together when all of a sudden he realises that he's past his exit. "F**k it" he shouts, and determined not to have to drive up to the next exit stops the car and kicks it into reverse backing his way up to the exit.

Next thing he knows another car is coming up from behind slamming on the brakes. The two cars almost stop in time, but not quite and collide. So Dave sits there for a second, not sure what to do, when his car is lit up with flashing blue lights. "Oh Balls" he thinks "F**kin cops, there goes my licence".

The cop stops behind the cars and gets out, walks to the first car and starts to chat to the driver. Dave is sitting in his car, looking at the cop in his rear view mirror, now feeling very sober and crapping himself. The cop talks for another few minutes, glances at Daves car a few times with a quizzical look, and then starts the slow walk up to Daves window.

"Oh crap oh crap oh crap" Daves thinkin. Here I go. Into the drunk tank. End of the licence. Maybe end of the job. Oh crap, and as the cop gets to Daves window he winds it down.

"Well sir," the cop says "are you ok?"
"Yes officer"
"Well, if you're all right you can go on. This guy back here is so drunk he's convinced you were reversing down the road."