There's an old couple, both in their 70's, on a sentimental holiday back to the place where they first met. They're sitting in a pub and he says to her, "Do you remember the first time we had sex together over fifty years ago? We went behind the barn. You leaned against the fence and I made love to you from behind."

"Yes, she says, I remember it well." she replies.

"OK, he says, How about taking a stroll round there again and we can do it for old times sake?"

Smiling his wife responds, "Oh Henry, you devil, that sounds like a good idea, she answers."

There's a man sitting at the next table listening to all this, having a chuckle to himself. He thinks, I've got to see this, two old timers having sex against a fence. So he follows them.

They walk haltingly along, leaning on each other for support, aided by walking sticks. Finally they get to the back of the barn and make their way to the fence. The old lady lifts her skirt, takes her knickers down and the old man drops his trousers. She turns around and hangs on to the fence and the old man moves in. Suddenly they erupt into the most furious sex the watching man has ever seen. They are bucking and jumping like eighteen-year-olds. This goes on for about forty minutes. She's yelling Ohhh God! He's hanging on to her hips for dear life.

This is the most athletic sex imaginable. Finally, they both collapse panting on the ground. The guy watching is amazed. He thinks he has learned something about life that he didn't know. He starts to think about his own aged parents and wonders whether they still have sex like this.

After about half an hour of lying on the ground recovering, the old couple struggle to their feet and put their clothes back on. The guy, still watching thinks, That was truly amazing, he was going like a train. I've got to ask him what his secret is.

As the couple pass, the guy says to them, "That was something else, you must have been shagging for about forty minutes. How do you manage it? Is there some sort of secret?"

"No, there's no secret, the old man says, except fifty years ago that f**king fence wasn't electrified."