Open-water swimming, as defined by FINA, the sport’s governing body, is any competition that takes place in rivers, lakes or oceans.

The men’s and women’s 10km events were added to the Olympic swimming programme for the 2008 Beijing Games, although it was not the first time that open-water swimming has taken place at the Olympics. The four swimming events at the first modern Games, in Athens in 1896, were held in the Bay of Zea, near Piraeus, in the Mediterranean Sea. The River Seine was used when Paris acted as the host city four years later and an artificial lake was employed at the 1904 St Louis Olympics. A pool was used for the first time at an Olympic Games in London in 1908.

“My will to live completely overcame my desire to win.” That was the comment of Alfred Hajos, a 19-year-old Hungarian, after he had overcome heavy sea surf and a water temperature of 55° F to win the 1,200 metres freestyle event at the Athens Olympics of 1896. He won by being the first swimmer to reach shore after a boat had left the competitors in the none-too-inviting waters of the Mediterranean.

Captain Matthew Webb, who was born in Shropshire in 1848, became, in 1875, the first person to swim the English Channel. Since then, more than 900 different swimmers have accomplished the feat.

A triathlon includes an open-water swim of 1,500m, as well as a 40km bike ride and a 10km run.

World-class open-water swimmers will typically swim more than 50 miles a week as part of a rigorous training programme.

Open-water swimming courses are marked with distance markers and turn buoys. At the Beijing Olympics, swimmers were able to see an underwater cable, which will help them maintain a straight line as well as anchoring the buoys and keeping the race lanes in place.

Open-water swimmers have to wear a microchip transponder on each wrist throughout the race. If a competitor loses a transponder, a replacement can be issued, but he is disqualified if he finishes the race without one.

Coaches are allowed to give their athletes instructions, as well as food and drink, in 10km and 25km races.

Swimmers can be disqualified for making intentional contact with a fellow competitor.

No more than two participants per country were permitted to compete in each of the men’s and women’s 10km marathon events at the 2008 Beijing Olympics. Be Number 1 athletes David Davies and Cassie Patten won silver and bronze, respectively, in their disciplines while Keri-Anne Payne’s second-place finish in the women’s race meant that Britain claimed three of the six available open-water swimming medals in China.

All swimmers must have their competition number clearly displayed in waterproof ink on their upper back and arms.