Britain’s defence arrangements are “not strong enough” to handle a more threatening world, Labour has said, pledging to reform the Ministry of Defence if it comes to power.

Shadow defence secretary John Healey said his party would introduce a new military strategic headquarters and appoint a national armaments director to overhaul military procurement as part of plans to improve Britain’s armed forces.

In a speech to the Policy Exchange think tank on Wednesday, Mr Healey agreed with Defence Secretary Grant Shapps that the world is moving from a “post-war” to a “pre-war” situation, saying it is “deeply sobering”.

He warned: “Over the next decade, we face (Russian President Vladimir) Putin and an active alliance of aggression – from autocrats who have contempt for international law and freely squander the lives of their own people.”

Mr Healey has previously criticised the Government’s defence plans, which would see the size of the Army cut from 76,000 regular troops to 73,000 – down from 97,000 a decade ago.

He has also pointed to problems with defence procurement, including the troubled Ajax programme for a new armoured fighting vehicle, saying military procurement processes have wasted more than £15 billion since 2010.

On Wednesday, he said the Ministry of Defence (MoD) “hasn’t been good enough at strategic preparation” and attacked the Government’s record on defence.

He said: “What signal have the Conservatives sent to our adversaries over the last 14 years by ‘hollowing out’ our armed forces, creating a recruitment crisis, and shrinking the Army to its smallest size since Napoleon?”

Mr Healey added: “As part of Labour’s plan for defence to fix this, we will establish a full-functioning military strategic headquarters within the Ministry of Defence to restore Britain’s military readiness, and a national armaments director to ensure our forces have what they need to fight. This will allow the UK to deter threats, defend the country and defeat any attacks.”

The strategic headquarters is intended to provide greater strategic oversight within the MoD and increase the authority and accountability of the Chief of the Defence Staff.

Defence chiefs will also see their terms in charge of the armed forces extended from two years to four.

The national armaments director would “secure better value for public money, cut waste and drive a new defence industrial strategy to make the forces fit to fight in the future”.

Mr Healey said: “The changes I set out today will mean a stronger strategic centre in defence to restore military readiness in Britain, to deter and if necessary fight the conflicts that threaten us.”