A decision by James Heappey to leave his role as armed forces minister means the military will lose a useful advocate who had been pushing for more defence spending from the inside.
The MP for Wells in Somerset and former army officer was also the most experienced member of the ministerial team at the Ministry of Defence, having joined the department in 2019.
Once he goes, it will leave Andrew Murrison – who oversees defence people and families – as the longest-serving defence minister. He joined the department in October 2022.
Mr Heappey, 43, announced on Friday that he would not be standing as an MP in the next election. He will stay on as a defence minister until the Easter recess when the prime minister is expected to appoint a successor.
A source close to the minister said his decision to resign was linked to personal issues rather than because of the defence budget.
Follow politics latest:
62 Tory MPs now standing down
However multiple sources said Mr Heappey had been a strong voice internally pushing for greater expenditure for the armed forces at a time of growing security threats.
His resignation comes amid growing concern within the military and among MPs about the UK’s ability to fight a war.
A failure by Chancellor Jeremy Hunt to announce any new money for defence in his spring budget caused widespread dismay among defence insiders, as well as with a growing number of Conservative MPs.
In an unusual move, two serving ministers last weekend broke cover to urge Rishi Sunak’s government to “lead the way” and increase defence spending to at least 2.5% of GDP – from just over 2% at present – “as soon as economic conditions allow”.
Anne-Marie Trevelyan, a foreign office minister and former defence minister, and Tom Tugendhat, the security minister and an experienced soldier, wrote in an online post: “The sad truth is that the world is no longer benign. Protecting ourselves requires investment.”
Several senior Conservative MPs spoke out more forcefully during an Urgent Question by Labour this week on the state of the armed forces to voice their concern about defence spending and urge for an increase.
Mr Heappey, however, stayed loyal to the prime minister as he announced his decision to step off the political stage and away from the Ministry of Defence.
In a letter to his Wells and Mendip Hills Conservative Association, the minister said he “will support Rishi Sunak as our party leader and prime minister in government, until such time as he wishes me to step down, and then from the backbenches”.
He may yet decide to make a more pointed intervention on military spending when he appears before MPs a week on Monday for defence questions in what will likely be his last turn as armed forces minister.
