Does holding it in really sharpen the mind?

The PM eschewed toilet breaks at the euro summit to aid his concentration. Will it work for Tom Peck? Fingers (and legs) crossed...

Wallop! The landing gear of my Boeing 737 smacks into the grass with a bang, some distance to the right of the second runway at Heathrow. "I'm afraid the wheels have gone through the wings," my co-pilot graciously informs me. "There will have been many fatalities."

It's a little embarrassing, but I don't hugely care. My eyes have become transfixed by the terminal building, and though it is merely a pixillated mirage on the screen of the flight simulator, my mind cannot prevent itself from imagining the many gentlemen's toilets that must lie within.

Whatever one thinks of David Cameron's decision not to sign up to Europe's new fiscal compact, by far the strangest detail to emerge is that, throughout the nine hours of negotiation crucial to the nation's finances, our Prime Minister was desperate for the toilet – but deliberately didn't go.

Perhaps we shouldn't be surprised by the outcome. Who would sign up to tighter budget constraints after waiting nine hours to spend a penny? The claim is it helps to maintain focus, and that he has deployed the tactic before, notably for his successful "no-notes" party conference speech in 2007 (this may go some way to explaining his continual pacing around the stage).

It is a tactic he is said to have picked up from the controversial Conservative politician Enoch Powell, who always delivered important speeches, including the notorious "Rivers of Blood" address, on a full bladder. "You should do nothing to decrease the tension before making a big speech," Powell said. "If anything, you should seek to increase it." Mr Powell can claim some expertise in the field of tension raising, if nothing else – but as most people outside the English Defence League will testify, he did sometimes get things wrong, and on this front the science is against him.

A study published in the journal Neurourology and Urodynamics concluded that "extreme urge to void [urinate] is associated with impaired cognition".

The study's author, the University of Melbourne's Dr Paul Maruff, found that "the degree you can't concentrate is much bigger than (having a blood alcohol level) of 0.05. It's worse than if you haven't slept in 24 hours." So is Mr Cameron wrong? Or is it indeed a case of "full bladder, full mind", as no philosopher ever speculated? In the interests of science, I decided to put what Neurology and Urodynamics calls my "spinal and supraspinal inhibitory and excitatory networks" to the test. With three litres of water on board I take my seat in the cockpit of the Boeing 737-800 simulator, newly installed at a shopping centre.

There is quite a lot to take in. "This is the thrust, this is the speed," explains Alex, patiently pointing to the countless instruments, then setting off on a technical talk. Unfortunately I appear physically incapable of listening to a word that is said.

The take-off goes okay, but when asked to "cruise" at 4,000 feet for a few minutes I am feeling pretty furious. "Can we not just land the thing?" Which we duly do, but it does not go well. "Nose up" and "nose down" have become interchangeable terms in my mind, which is focused elsewhere. Shortly after this point I smack into the grass, killing all on board.

The second challenge, just as taxing, is a little more mundane: University Challenge. A further three litres back on board, that famous music begins. Again, I am overcome by waves of anger. I don't think it would be medically possible to care less what Mukherjee from Pembroke College Cambridge is reading. One can only hope, for poor Mr Sarkozy's sake, the same symptoms do not manifest themselves in our leader.

I do fairly well, perhaps better than normal, and the answers come faster. There is an undoubted urgency. My usual lag between the halfway-mark music round and the second set of pictures, where my flatmate usually moves away from me, is not forthcoming. "The Picture of Dorian Gray!," I shout. "Seattle! Stravinsky's 'Rite of Spring'!" Have some of that Mukherjee. Perhaps there's something in this.

One detail, however, is crucial. During the long night of negotiations, while other leaders apparently "knocked it back", Mr Cameron drank only black coffee. But Challenge Three, to test my mettle with the fairer sex during a night out on the town, will require a deviation from this rule. Ordering a black coffee doesn't seem like the done thing in a nightclub so, in the interests of science, I opt for lager. Five bottles see me approach a blonde woman at the bar.

I have probably overdosed. I manage a tentative: "Hello, would you like a drink?" But the sound of the word, with its watery connotations, is like a babbling brook as it leaves my mouth, and I panic yet further. Aloe Blacc has taken to the club's stage, singing "I Need a Dollar", and I rush to the welcome oasis of the gents and part with a lesser denomination – precisely one hundredth of the glorious British pound.