Next to the pool, competitors performed the timeless seaside contortion of donning swimsuits beneath towels. Others queued for last-minute massages or compared newly shaved pates. Smart officials prowled the side of the pool making sure that no one butterflied when they should have crawled, and vice-versa, and got their nice white trousers soaked for their trouble.
All the while the PA called the rolls of the heats, and phalanxes of swimmers plunged in at one end of the 50-metre pool and wriggled out at the other, like high-speed sheep in a super-dip.
The stars were no less impressive for being unannounced. Mark Foster proved that he has moved on from bad boy to badly organised man by failing to register in time for the 50m freestyle. This meant he had to swim out of turn in a weak heat but he hardly seemed flustered as he churned smoothly down the pool to qualify comfortably for his final. Adam Ruckwood made similarly straightforward progress backwards in the heats of the 200m backstroke.
Competition was fiercer among the women, particularly when Sue Rolph and Karen Pickering resumed their keen rivalry in the heats of the 100m freestyle. The strongest swimmers were seeded so that Pickering and Rolph occupied lane four in successive contests.
Such was the turnover that those who had just finished got their breath back at the end of the pool as the next competitors lined up. So while Pickering recovered, Rolph dived over her head in pursuit of her time.
They both qualified with ease and after her heat Rolph, the 19-year-old from Newcastle who is widely regarded as a future Olympic medallist, played down the notion that she and Pickering were at daggers drawn. "It's the same in every sport," Rolph sighed. "I'm always reading that Karen and I are fierce enemies but actually we get on fine. We have a laugh and it's all part of the team spirit."
Rolph, in common with other top swimmers who have already qualified for next month's European championships in Spain, regards the nationals as a nice sharpener and a chance to catch up with old friends. "There are quite a few of us who aren't shaved and tapered," she said, referring to the cosmetic fine- tuning that competitors undertake before vital contests. "So it's possible that some of the other competitors could spring a surprise. But that wouldn't be the end of the world."
As well as the 100m freestyle, Rolph was also swimming the 50m butterfly at Crystal Palace. But her forte is the 200m medley, for which she has both a European record time and a gold medal. "I like training for the medley," she said, "because I get bored after three lengths doing one stroke and it's fun to switch to another. It keeps me sharp."
Boredom is more of a danger than burn-out now that swimmers can expect long and lucrative careers. "I've been on the circuit for four years now, but I'm still only 19," Rolph said. "I've got a long way to go and there's more speed and strength to come. I'm setting personal bests yet I'm still girly compared to some of the foreign swimmers."
The only dead leaf in her personal pool is constant comparisons with Sharron Davies. "People tell me I should be flattered because she was a medley swimmer, she's bubbly and articulate and so am I. But for God's sake, I've already broken her record and while it might be nice to present The Big Breakfast in the distant future, I've got other things on my mind at the moment." What sort of things? "New British records..."