Obviously you're not supposed to go to the loo while the train is at a station.

But, if the train has been stuck at the station for the past hour and a half then you'd have thought the powers that be would make exceptions.

That's what I thought anyway, until the driver of the train started banging on the door and demanding access.

By virtue of oversleeping (OK so habitual tendency to oversleep is more of a vice) had missed a few of the regular trains, which I should catch in order to be at desk on time, and instead catching the 8.57 Thameslink service.

This went as far as Hassocks and then stopped. Nothing happened.

More nothing happened. After a while the driver, who was running the show single handedly (guards long abolished on Thameslink trains), tried to make an announcement - but his pa system appeared to be broken, along with his train, so nobody could actually hear what he was saying.

After about half an hour of sitting there trying to comprehend the muffled voice of the driver, as he tried to keep us informed, my mind began to turn to thoughts of needing the loo. But knowing you mustn't go while train is in station, I tried to think about other things: like the fact that as I was running late I hadn't bought a paper and had nothing to do except think about going to the loo.

At this point the station announcer decided to help out the poor old driver with his broken pa by informing us that the train was stationary due to a broken train further up the line and we would have to patient while it was fixed, but in the meantime, as a way of compensating passengers, there would be free water available in the station.

Stuck head out of window and noticed that they'd erected sign giving pretty much the same information on platform, only they appeared to have run out of Ts - so it informed us that we were stuck due to broken down 'RAIN' further up the line.

All this talk of free water and rain only served to make me even more desperate. So decided that, in event of being stuck in one place for over an hour, toilet rules no longer applied - even if extra nitrogen on track would cause excessive growth of plants, causing further delays.

Had just closed the door of toilet when there was a knock on it and the driver identified himself and asked if there was anyone in there. So out I came, explaining that because we'd been stuck there for so long I'd become desperate and hoping to be let off with a caution. But it turned out driver was not in pursuit of people who break the toileting rules, but trying to fix fuse of pa system, which for some reason appeared to be located in toilet.

I returned to seat, he fiddled about and appeared to have some success because when he returned to his cab was able to tell us that they were sending a new train (or rain) up from Brighton and we would shortly be on our way.

Which we were - only an hour and a half late. Though now that the driver had fixed his pa system the powers that be appeared to be giving him no information to pass on to us through it. I know that because he told us this, saying that we would be leaving the station soon and might be going straight to East Croydon, without stopping anywhere on the way, in order to make up a little lost time - but he wasn't sure because nobody was telling him anything.

In the event we left, but did make several stops along the way, one of which was Gatwick, where several people with several suitcases crammed into the carriage, blocking all exits and doorways, including the door to the toilet.

Which was when I remembered that I still needed to go....