This is reported by the British Defense Ministry on Twitter.
British intelligence notes that Russia has begun expanding its defensive positions along its border with Ukraine and the Belgorod region. On December 6, the local government announced the creation of local self-defense units. Trench digging in Belgorod has been reported since April 2022, but the new structures are likely more complex and designed to repel attacks using armored vehicles.
"There is a realistic possibility that the Russian authorities are promoting defensive preparations within internationally recognised Russian territory to burnish patriotic feeling. However, it probably illustrates some Russia decision-makers’ genuine (but false) belief that there is a credible threat of invasion by Ukrainian forces," the British intelligence service suggests.
They also concluded that the lack of strategic assessment is one of the critical weaknesses of the central Russian government architecture. First of all, this was evidenced by Russia's decision to break into Ukraine.
"Impartial official analysis is almost certainly frequently undermined by a tendency toward group-think and politically expedient conclusions," the analysts said.