Skelton’s time of 39.98 seconds left Toomey with it all to do on Tinka’s Serenade, and he retired after having the second fence down.

Toomey could have won it in “normal time” for the Irish, but he failed to deliver the clear round required, meaning a jump-off was needed to decide the Aga Khan Trophy winners.

It was Britain’s first Nations Cup triumph this season, and their first in Dublin since 2008. They now head to the Rotterdam finale later this month just four points behind leaders Holland.

Britain are equal-second with Germany, just half a point above Ireland, but reigning Olympic team champions the United States are facing possible relegation to the second-tier Promotional League alongside Denmark.

Dublin also marked a successful return to the saddle for Michael Whitaker.

Whitaker, a former world number one, was arrested but not charged following his involvement in a hotel fracas near Hickstead last weekend.

He missed the final two days of this year’s Longines Royal International Horse Show – including the prestigious King George V Gold Cup – before apologising for his behaviour and making a donation to charity.

The 51-year-old was retained in Britain’s Nations Cup team for Dublin, and he rewarded team manager Rob Hoekstra’s loyalty by playing a key role aboard GIG Amai.

Whitaker had four faults and a clear, matching Robert Smith’s performance on Talan, while Scott Brash and Intertoy Z had 12 and four.