The UK's fleet of submarines will receive upgraded Tomahawk Land Attack Missiles thanks to a new £265 million contract.
The Royal Navy's Astute-Class submarines will be armed with an enhanced Block V standard missile - weighing roughly the same as a 4x4 car.
Capable of travelling further than the previous version, the upgraded missile will also make the weapon less vulnerable to external threats and comes with modernised in-flight communication and target selection.
Due to be operational in the mid-2020s, the upgraded Tomahawk will align with the delivery of the latest Astute-class submarines.
Jeremy Quin, Minister for Defence Procurement, said the upgrade will provide the submarines with "one of the most lethal and precise long-range strike weapons".
"Enhancing this cutting-edge missile system will ensure the UK can strike severe threats up to 1,000 miles away," he said.
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Measuring 5.6m long and weighing 2,200kg, the Tomahawk first entered service in 1998.
It can hit land targets from the sea within minutes and has been deployed on operations in Afghanistan, Libya and Iraq.
The upgrade is part of a Foreign Military Sale with the US Government.
Making use of existing US research and expertise on the upgraded missile, the contract will mean the UK continues to receive full access to the US Tomahawk programme, support package and upgrades.
Rear Admiral Simon Asquith, Director Submarines, said the missiles give the UK "real strategic and operational choice".
"Able to be fired from a stealthy UK nuclear attack submarine, the system's exceptional range, accuracy and survivability provides the UK, alongside our US Allies, with a world-beating precision strike capability," he added.
The £256m contract also includes missile maintenance, recertification of existing missiles, spares, operational flight testing, software, hardware and training provisions.