It is asking people to wear a hat to work for a day or the rest of the week and collect a donation for their efforts to go towards the society's work caring for seafarers, who spend many months at sea transporting goods around the world.

The fundraising week is inspired by the woolly hat, which may be an optional extra for people on dry land but is an essential item of clothing for seafarers, many of whom come from warm regions and may not be used to the cooler temperatures in the UK and North Sea ports.

As part of its work supporting seafarers, the Sailors' Society hands over more than 15,000 woolly hats knitted by volunteers each year, around 6,000 of them being gift wrapped for presents every Christmas.

As well as being a useful practical gift, giving a seafarer a woolly hat shows them that someone is thinking about them and cares.

Among those showing their support for the Woolly Hat Week is Geoff Holt MBE, Yachtsman of the Year and the first quadriplegic sailor to cross the Atlantic solo.

The week runs until February 12.