Thursday evening's Manxman sailings to and from Heysham were cancelled after the vessel's sprinkler system was activated by a faulty air conditioning unit.

Passengers were on-board the ship waiting to depart for Lancashire yesterday evening when the incident happened.

A Steam Packet statement said: 'Initial investigation suggests the system was triggered automatically following the failure of an air conditioning unit.

'The air conditioning unit released refrigerant gas that was detected by the vessel’s sensors, leading to the activation of the sprinklers.

'The fire detection and suppression system functioned correctly in response to detecting gas. At no point were any passengers or crew in danger.'

Steam Packet managing director Brian Thomson added: 'In the first instance I’d like to apologise to all customers affected by the cancellations.

'Our reservations team have been working hard to make alternative arrangements where possible.

‘While we fully understand the frustration, it is ultimately encouraging to know that the system seems to have functioned exactly as it was designed to.

'As always, safety is our first priority and we’re fully investigating the circumstances surrounding this incident in order to learn any relevant lessons for the future.’

The Manxman resumed services this morning (Friday).