LONDON, July 14 (Xinhua) -- Britain's new flagship polar ship, capable of breaking through meter-thick ice, was launched Saturday in a ceremony on the River Mersey, the largest civilian ship to be built in the UK for 30 years.

The 10,000-tonne hull of the ship, named after the famous "Blue Planet" naturalist Sir David Attenborough, was built at the Cammell Laird shipyard in Birkenhead.

Attenborough, who is in his 90s, pushed the button to send his namesake ship into the river during the high tide on its way to an adjoining wet basin where it will be completed.

Shipyard workers, engineers, scientists and maritime industry experts gathered to watch the historic launch of the 265 million U.S. dollar ship.

A military field gun fired as the ship entered the water.

Commissioned by the National Environment Research Council (NERC), the new 129-meter long ship will be operated by the British Antarctic Survey, with enough space to accommodate 90 scientists.

Attenborough said: "This wonderful new research ship will enable British scientists to continue their crucial work in both the Arctic and Antarctic for decades to come."

An official handover of the finished ship is scheduled for the end of the year when the RRS Sir David Attenborough will begin sea trials, and go on its maiden expeditions to the Arctic and the Antarctic.

Captain Ralph Stevens from the British Antarctic Survey said: "One of the main trials we have to do is in sea-ice. We'll take her up into the Arctic and test her performance in the floes and that will give us a really good yardstick to know how far we can push this vessel. Her first year, 2019, is really a rehearsal year when we test everything onboard. In 2020, she'll be fully operational."

The new ship will replace the two existing polar vessels, the RRS James Clark Ross and the RRS Ernest Shackleton, with nearly 50 years' service and expensive to run as they age.