U.K. Defense Secretary Michael Fallon called for British lawmakers to support the Royal Navy's submarine programs during a speech on Wednesday.

Citing emerging security threats around the world including Russian expansionism, weapons proliferation, an increase in nuclear states, and the desire by "rogue nations" to acquire nuclear capabilities, Fallon asserted Britain and its partners can't "wish away" the threats.

"Today I appeal to all moderate MPs, to put our national security first and to support building four new Trident submarines," Fallon said. "First and foremost, it's about deterrence."

The U.K. Trident program includes the development, procurement, and operation of British nuclear weapons. The U.K. Ministry of Defence is currently in the process of developing a new submarine to replace the Vanguard-class submarines currently in service, which are armed with Trident II D-5 ballistic missiles.

Fallon added Russia is in the process of building eight ballistic missile submarines, and that while the country's ordered conventional submarines are late, the ballistic missile submarines cannot afford to be.

"Our adversaries are certainly not going to wait," Fallon continued. "So our shipbuilding industry and our deterrent have never been more vital."