Britain would struggle to match Russia’s military capabilities on the battlefield, the head of the U.K. army will say in a speech on January 22.

In an address to the Royal United Services Institute, Chief of the General Staff Nick Carter is expected to say Russia is building increasingly aggressive and expeditionary forces while already demonstrating its use of superior long-range missiles in Syria.

The speech, which was approved by Defense Secretary Gavin Williamson, will warn that Britain risks falling further behind potential adversaries unless it increases investments in its military operations.

“The time to address these threats is now — we cannot afford to sit back,” he is expected to say, according to military officials.

“Our ability to pre-empt or respond to threats will be eroded if we don’t keep up with our adversaries.

“We must take notice of what is going on around us or our ability to take action will be massively constrained.

“Speed of decision making, speed of deployment, and modern capability are essential if we wish to provide realistic deterrence.”

Defense chief Williamson has made it clear that he wants more funding for the NATO country’s military.

Conservative Member of Parliament Johnny Mercer, a former army officer, raised concerns about defense readiness after unconfirmed reports surfaced that the U.K. military was planning to cut its force by 14,000 service personnel, nine warships, and 100 helicopters.