Boris Johnson’s military strategist joined the Prime Minister at Nato’s top table amid questions over who will lead Labour’s defence review.

Earlier this week, Prof John Bew joined Sir Keir Starmer, along with John Healey, the Defence Secretary, and David Lammy, the Foreign Secretary, for high-stakes talks in Washington, around a table shared with Volodymyr Zelensky, Ukraine’s president.

As a No 10 foreign policy adviser, Prof Bew oversaw the integrated defence and foreign policy review in 2021 which, among many other moves, saw troop numbers cut to their smallest size since the Napoleonic era.

He was later involved in the review’s refresh last year, which was published in light of Russia’s invasion of Ukraine.

The defence command paper 2023 concluded that fewer troops would be needed on future front lines because of the rise of AI, as it defended its decision to cut troop numbers by nearly 10,000, as set out in its original version.

At the start of the week, Sir Keir announced Labour’s “root and branch” Strategic Defence Review that would look at “everything on the table” across defence and also left the door open to potentially increasing troop numbers.

The review, which is due to be launched next week, will also set out a “road map” to raising defence spending to 2.5 per cent of GDP.

Sources had speculated that Prof Bew would not serve under Sir Keir because of his close links to the Conservative Party.

However, given his front row seat in Washington this week, many have speculated he will remain.

But while it is customary for governments to keep senior political appointees on, Ben Barry, senior fellow for land warfare at the International Institute for Strategic Studies, asked if Prof Bew would be able to explain the “weaknesses and omissions” in the last two integrated reviews, given his involvement.

He said: “Those people working on this review who worked on the previous reviews, like Prof Bew, Admiral Sir Tony Radakin, the Chief of the Defence Staff, and other senior officials should acknowledge the weaknesses of the previous exercises, to reassure the Armed Forces and defence industry.”

He added that “external defence experts” should also be consulted.

Lord Dannatt, the former Army head, said he would be disappointed if the same people were left in charge of the latest defence review.

“The original integrated review of 2021 said what it said and then the refresh said it all again,” he told The Telegraph. 

“If we have the same person at the heart of it a third time, how fresh is this going to be? How new will it be?”

Lord Dannatt added that while he has “no criticism” of Prof Bew, he felt that “a new government ought to identify fresh minds and fresh thinking”.

“There are a lot of good people around,” he said. “Don’t just go for those who held the pen in the past.”