"It's a team that's ready to support any action if it becomes necessary," the spokesman said, adding that the new centre has "all the right infrastructure".

"As we get closer to a theoretical or possible no-deal, this is the place where the response could be co-ordinated", the spokesman said.

Britain is due to leave the European Union on March 29 without a deal, unless one can be agreed in time or an Brexit extension is implemented.

The defence ministry in December said 3,500 military personnel would be on stand-by to help government departments for "any contingencies" in case of a no-deal outcome.

The spokesman said those troops were now "at readiness".

The military's crisis management operation for a no-deal Brexit, which is dubbed "Operation Redfold", was activated at the beginning of this week.

The bunker is underneath the Ministry of Defence's main building in Whitehall and is the facility used in times of national emergency, British media reported.

Military personnel could be used to help transport food, fuel and other goods into and around the country in case of delays at the border, the reports said.