Quite how the key got broken off in the lock was something of a mystery. John blamed Sherlock. And of course Sherlock blamed John. But of course the end result was the same either way. They were locked out on the landing and couldn't even pick the lock because they couldn't get the broken bit of key out of it. And Mrs Hudson was out. Sherlock was all for climbing up the front of the building and getting in through a window. John was all for breaking the door down. The third, less violent and potentially fatal option was to await Mrs Hudson's return and borrow a pair of pliers.

It was quite chilly on the landing. And within a few moments Sherlock was complaining of cold and boredom. John could think of several ways to alleviate both of those conditions. Just not on the landing, when Mrs Hudson could walk in at any time, potentially with friends from the Women's Institute in tow. Absolutely not. But of course as soon as the thought had popped in to John's head, he found it impossible to think of anything other than pulling down Sherlock's trousers and having him on the stairs.

Not good.

He stood up and stamped his feet a little. Realising too late that his groin was now at Sherlock's eye level. He really was going to have to buy a longer coat.

"What an excellent idea John."

"What is?"

"Having sex on the stairs."

"No. I meant it. No. Completely. No." But the Holmes hands were already on John's belt and pulling him and his bulging jeans in the direction of down. John realised it was a lost cause and thought it might be okay as long as they were quick.

Sadly not quick enough as it turned out. Mrs Hudson opened the front door and was greeted by John Watson's bare arse at the top of the stairs, thrusting back and forth, and a pair of bony feet dangling off the landing that she presumed were attached to the rest of Sherlock. She stood transfixed for a moment before deciding to go and put the kettle on, and maybe have a sherry, whilst they finished.

John was so engrossed in ploughing Sherlock's furrow he didn't notice the influx of cold when the front door was opened. Sherlock did of course, but thought it was probably best not to say anything.