Dave was born a couple of hours before me. On this trivial basis, he’s always pulled rank. Still, basically, we got on fine. We shared a flat and worked as website designers for the same company. We went for the same type of girl.

This had never caused a problem, until last year. We were on holiday in St Lucia, as part of a group: five blokes and six girls. Three were taken; that is, besides us, there were three couples. That left three girls, Rhona, Cathy and Sal.

Rhona was seriously overweight, and her underslung jaw didn’t help the overall effect. Cathy was the reverse: achingly thin, with a sharp chin that might cause bruises. Fortunately, the third girl, Sal, needed no adjustment.

As soon as we got off the plane, we knew she was tailor-made for us. We liked it when a single girl suited us both. It was a real buzz. As good as deep-sea fishing. Dave led; he spun out the line and waited for the bite; then I came in.

We took turns, reeling in and out. We always agreed which one of us would finally haul the fish aboard.

Sal, though, was — apologies for the pun — a different kettle of fish. With her laughing eyes and mass of long, black curly hair, she immediately made us competitors.

Dave managed to get the seat beside her on the minibus to the hotel; I was forced to take the one behind. Even though I leant forward as far as I could, I couldn’t hear what they were saying.

Anyone would have thought they were old friends. And they’d only just met.

“My turn,” I told Dave when we got off the bus, and I grabbed her suitcase. She was confused for a moment, then laughed. “Oh, you’re twins,” she said, tossing her hair with delight. “How fab-u-luss!”

It might have been fabulous for her. It certainly wasn’t for me. At first, I thought my gut ache was due to St Lucian food. Then I realised it was pure and simple jealousy.

For the first week, Dave and I waged a kind of war. We tried to outwit each other with strat­egies, such as being first up and first to spot in which direction Sal planned to go that morning — to the pool, to the beach or for a stroll into the local town. We dodged around the market, trying to be at her elbow at the right moment, each attempting to get ahead of the other. It was a strain.

Then, one night, I came up with a radical plan. There was something so neatly natural about it, it hardly needed subterfuge. Dave had promised our boss that he would stay in regular contact. I knew from my own e-mails with the

office that Dave was in the mire. They kept asking me to get him to text, e-mail, phone — to do something, anything. It seemed the huge contract he had left in mid-flow was in jeopardy, and if they were left with no more contract, shortly afterwards there would be no more Dave.

I prompted him several times, out of sheer brotherly love and support, but he clearly thought I was trying to lure his attention away from Sal. He didn’t respond.

I’m not a nerd for nothing. I manufactured a message as though from the office to come through the hotel’s system. It ordered him to take the next plane home — or else.

The phrasing was so auth­entic that Dave did indeed get the next plane home. He never learnt my part in this. He secured the contract and got a big rise. I got a big rise, too. Sal’s been my girlfriend ever since.

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