Mixed relay dubbed “one of the most exciting races in swimming”

“It’s because of the lead-changing and tactically seeing what the countries do, and how they approach it. It’s a really fun one,” said Adlington, who is now part of the BBC’s swimming commentary team.

This sense of enjoyment seems to be the key asset behind one of the newest events in elite swimming. The mixed medley relay made its debut on the global long course stage at the 2015 FINA Aquatics World Championships in Kazan, Russia; and the swimmers, crowd and television viewers appeared to give it a universally rapturous reception.

“You are sitting there as a (TV) viewer and you think, ‘well, we are out of this’, and then you are like, ‘actually, no we are not, we have got so-and-so coming next, and it’s a guy up against a woman,” explained Adlington’s fellow BBC commentator and five-time Olympian, Mark Foster.

The potentially dramatic reversals in fortune, with the lead often endlessly changing hands within a race, are certainly a huge draw. Teams are free to choose their line-ups as they please, making strategy key and predictions difficult.

“If you look at it, the four best swimmers on paper should win; but it depends on how you set the relays up – for example you can send the guys out first and get clear water and then create a lot of wash for the women at the back to try and get through,” Foster said.

“There will be a lot more cat-and-mouse going on, a lot more tactics involved, without a shadow of a doubt.”

This, for the competitor in Adlington – she won the 400m and 800m freestyle titles at the Beijing 2008 Games – is what makes it such fun for the swimmers.

“It is such a fast-paced event. A lot of guys will be absolutely buzzing (at the inclusion of the event for the 2020 Games),” she said.

The 28 year-old, who also won two bronze medals at the London 2012 Games, knows what she is talking about. She is one of the few elite swimmers from a previous era to have participated in a mixed relay.

“I think it was at the European Youth Olympics (the 2003 European Youth Olympic Festival in Trabzon, Turkey) we swam a mixed 4x200m relay. I was really young and I loved it. It was great to be part of the team, racing with the boys. It was just so exciting,” she said.

Both Adlington and Foster, who is a six-time short course world champion, profess to having “loved swimming the relays”, and are gutted they never got the chance to compete in a mixed gender event at the very top level. When asked who from their era they would like to have swum with, Adlington wastes no time in picking her freestyle swimmer.

“Mark Foster,” she said unequivocally. “He is a pure sprint guy and we are great mates now. It would have been amazing to be part of a relay sprint team with him.”

Laughing, the former 800m freestyle world record-holder added Great Britain’s two-time 50m backstroke world champion Liam Tancock and two-time Olympian and relay star Fran Halsall to her mythical British quartet.

When it comes to nominating an all-time greatest team to have participated in, the laws of physics and nationalities aside, both Adlington and Foster agree on one thing instantly.

“You’d have to say (Michael) Phelps on the butterfly, obviously. That is an absolute given, he is 100 per cent,” Adlington said, with Foster calling it a “no-brainer”.

Elsewhere, Adlington nominated one of Australia’s Campbell sisters (Bronte is the reigning 50m and 100m freestyle world champion, and Cate is the current 100m freestyle world record-holder), and Aaron Peirsol, the USA’s three-time backstroke and two-time medley relay Olympic champion. In contrast, Foster went for legendary female backstroke champion Krisztina Egerszegi, who won the 200m backstroke at three consecutive Olympic Games between 1988 and 1996, and London 2012 100m breaststroke champion Ruta Meilutyte.

It would make a cracking race to match up these two teams, although modestly both Adlington, who complained she “can’t sprint”, and Foster, who said he wouldn’t “last 100m”, tried to rule themselves out of such company.

Excitement levels high, the two Olympians each highlighted one final plus point of the new event. For Adlington, the battle to be a part of the team in the build-up to the Olympic Games will add an extra seam of interest for the public. While for Foster, it offers a tangible boon for smaller nations.

“Where it will help is some of the countries that just don’t have so much depth; it will make them more competitive,” he explained. “Your powerhouses like the USA will always be strong, but others only need two good women and two good men.”