Iona was launched on Sunday night with a naming ceremony in Southampton Credit: P&O Cruises What could gin, low emissions and Gary Barlow possibly have in common? They all play key roles in Iona, the latest addition to P&O Cruises' fleet. Launched last night with a naming ceremony in Iona's homeport, Southampton, she is Britain's largest and most environmentally friendly cruise ship to date. Fuelled entirely by liquefied natural gas, Iona – P&O's first next-generation, Excel-class ship – generates minimal exhaust emissions, with significantly less CO² and zero nitrogen or sulphur. Innovations around the ship include an extraordinary 'SkyDome', the first gin distillery at sea and the 710 Club: a live music venue helmed by Take That's Gary Barlow.