Viking River Cruises has confirmed that it has an option to build six more Longships in 2014 – on top of the six it has already confirmed will be delivered in 2013 and the six that will enter service this year.

Chairman Torstein Hagen told guests at the glittering christening ceremony for the first four Longships for this year that the fleet size could reach 35 by 2014 – from just four 15 years ago.

Hagen was speaking after the ceremony in Amsterdam at which Viking’s latest ships – Odin, Idun, Njord and Freya – were christened by four godmothers including Joanna Lumley.

Two of the ships – Njord and Freya – are still at the shopbuilders yard in Rostock and will come into service in mid-April.

A fifth ship will join the fleet in June and the sixth will be delivered in August.