He was the Southampton master mariner who saved more than 700 lives after the Titanic sank on her maiden voyage in 1912.

Now, a gold pocket watch presented to Captain Arthur Rostron by three of the grateful survivors has sold for a record-breaking sum.

A private collector in the US has bought the 18-carat watch for £1.56m - the highest sum ever paid for an item of Titanic memorabilia.

Captain Rostron, who lived at West End, was master of the RMS Carpathia on the night the Titanic sank after hitting an iceberg.

The RMS Carpathia dashed to the rescue of Titanic survivors after the liner sank in 1912The RMS Carpathia dashed to the rescue of Titanic survivors after the liner sank in 1912 (Image: Supplied)

After the crew intercepted a distress signal from the ill-fated liner, he ordered them to turn Carpathia around and head for her reported position.

The ship took three-and-a-half hours to reach the scene of the disaster, arriving long after the Titanic had sunk.

READ MORE: Titanic hero Arthur Rostron lived at Chalk Hill in West End

People plucked from her lifeboats were taken aboard Carpathia, which was fully prepared for their arrival thanks to a long list of instructions that had been issued by Captain Rostron.

His quick thinking and heroic actions resulted in the rescue of 710 passengers and crew.

The Titanic was on her way from Southampton to New York when she sank after hitting an icebergThe Titanic was on her way from Southampton to New York when she sank after hitting an iceberg (Image: Supplied)

Captain Rostron was awarded a Congressional Gold Medal by the United States Congress and knighted by King George V in 1926.

He was also presented with a Tiffany & Co watch by the widows of three wealthy businessmen who died when the Titanic went down. Despite their grief, they wanted to thank him for saving so many lives.

Now, the historic timepiece has been sold by auctioneers Henry Aldridge and Son in Devizes, Wiltshire.

READ MORE: Granddaughter of Carpathia's captain visits Southampton port

An inscription on the watch reads: "Presented to Captain Rostron with the heartfelt gratitude and appreciation of three survivors of the Titanic April 15th 1912 Mrs John B Thayer, Mrs John Jacob Astor and Mrs George D Widener."

The presentation took place at the Astor family's mansion on Fifth Avenue, New York.

Auctioneer Andrew Aldridge said: "It was presented principally in gratitude for Rostron's bravery in saving those lives, because without Mr Rostron, those 700 people wouldn't have made it."

Captain Rostron rose to become Commodore of the Cunard fleet.

Following his retirement in 1931 he became a member - and later captain - of the Southampton Master Mariner's Club, and also wrote his autobiography, Home from the Sea.

He and his wife were visiting their daughter in Wiltshire when he was taken ill. He developed pneumonia and died on November 4 1940, aged 71.

His funeral took place at West End Parish Church on November 7. His widow died three years later.