The British government has confirmed it is developing a new nuclear warhead for its missile submarines.

In a written statement to Parliament, Defence Secretary Ben Wallace confirmed Feb. 25 that Britain is working on a new warhead to equip it’s Trident missile-armed nuclear submarine fleet.

“To ensure the Government maintains an effective deterrent throughout the commission of the Dreadnought Class ballistic missile submarine we are replacing our existing nuclear warhead to respond to future threats and the security environment,” Wallace said.

Wallace told Parliament that the Defence Ministry’s “Defence Nuclear Organisation is working with the Atomic Weapons Establishment: to build the highly skilled teams and put in place the facilities and capabilities needed to deliver the replacement warhead; while also sustaining the current warhead until it is withdrawn from service. We will continue to work closely with the US to ensure our warhead remains compatible with the Trident.”

The new British warhead will replace the existing weapon, known as the Trident Holbrook, which equips the four Vanguard-class submarines charged with providing Britain’s nuclear deterrence capability.

The Trident Holbrook entered service along with the Vanguard-class submarines in the mid-1990s. Britain plans to replace the subs in the early 2030s with four new Dreadnought-class subs.