That added to the 200m breaststroke bronze won by Chemical Engineering graduate Andrew Willis on day two of the event in Netanya, with Great Britain – led by British Swimming National Centre Bath Head Coach Dave McNulty – winning 11 medals in total during a successful championships.
Carlin’s second gold came on the last day and in thrilling style as she beat Hungary’s Katinka Hosszu by just three-hundredths of a second in the 400m freestyle final.
The winning time of 3:58.81 was a new personal best for Carlin, who was overtaken by Hosszu with 50m to go but dug deep to claim her second victory of the week. Hungary’s Boglarka Kapas won bronze.
Walker-Hebborn secured Britain’s last medal of the championships when he finished joint second with Simone Sabbioni of Italy in the 50m backstroke final. The silver-medallists both set times of 23.09 – a new British record for Walker-Hebborn – as gold went to Poland’s Tomasz Polewka in 22.96.
There was another strong performance by Walker-Hebborn in the 100m final as he won bronze in 50.35, behind Radoslaw Kawecki of Poland and Russia’s Stanislav Donets.
O’Connor was only beaten by double World Champion Hosszu in both of her medley finals and it needed a new world record time of 56.67 to deny the Brit in the 100m race.
O’Connor clocked 57.65 in that event and then set a new British record of 2:05.13 as she secured a second silver in the 200m final.
Carlin, O’Connor and Willis are now heading to Indianapolis as part of a seven-strong British team taking on the United States in the annual Duel in the Pool on December 11-12.