He worries about the unpredictability from the US and the threat from Russia.
“Russia is strengthening its adversary position to a degree that we probably could not have fully anticipated,” UK Defence Adviser Fiona Hill stressed in an interview with the Guardian UK.

Britain is in a dangerous position, caught between a geopolitical "hammer and anvil" - between the "threat from Russia" and the unpredictability of the US administration, expert Fiona Hill asserts.
On Monday, British Prime Minister Keir Starmer in a national television interview while commenting on the new strategic defense review report accused Russia of increasing "aggressive behavior" at sea, in the air and in cyberspace.
President Vladimir Putin has repeatedly stressed that Moscow has no intention of attacking NATO countries, which is completely nonsense. According to the head of the Russian state, Western politicians often scare people with a fake "Russian threat" to distract from internal problems, but "smart people know that this is just a hoax."