Theresa May, this week, has asked the British secretary of defence to justify the UK’s position as a "tier one" military power.

The statement is a realisation that the UK can no longer economically compete with top countries, military experts told Business Insider.

Dr Jan Honig, a senior lecturer in war studies at King's College London said it is "highly ironic" that Brexit could mean the UK can longer fund its defence.

Julian Lewis, Chair of the UK’s defence committee told BI he is now "concerned about whether Theresa May will be able to give defence the money it needs."

Theresa May this week asked Britain's defence secretary to justify the UK’s role as a "tier one" military power, causing dismay in the Ministry of Defence. Underlying the statement is a realisation that the UK can no longer economically compete with top powers, defence experts told Business Insider.

"It’s a reflection of our economic status - times are tough," said Tim Ripley, a defence analyst, adding: "It’s all about money... if you don’t have money you can’t spend it."

The Prime Minister questioned defence secretary Gavin Williamson on whether money for the military should be reallocated to areas like cyber, and if Britain needed to maintain a Navy, Army, Air Force and nuclear deterrent all at once.

Ripley called it a retreat from "grand ambitions".

"No matter how we dress it up, this new fangled cyber stuff is just an excuse for running away from funding hard power," Ripley said. "If you don’t pony up the money and the hard power you don’t get a seat at the top table. No matter how flash your cyber warfare is, people take notice of ships, tanks and planes."

There is a strong link between military and economic power. Giants like the US and China show their strength through military posturing and countries that don’t have enough resources for defence often pool with others.

Dr Jan Honig, a senior lecturer in war studies at King's College London, said that shared defence can be disrupted in times of nationalism, and called it "highly ironic" that Brexit could mean the UK can longer fund its military.

"You can’t really do it by yourself even if you spent a lot more on defence which is not going to happen in this country with this measly economic growth and the uncertainty about international trade details," Honig said.

The Prime Minister’s comments, which were first reported by the Financial Times, come in the context of her recent pledge of a fresh £20 billion for the National Health Service (NHS) and debate about where the money will come from.

Governments need to ensure that their policies have support from the people, and pouring money into the military is harder to sell then spending on the NHS and social welfare which are immediate issues, said Honig, adding that populations are also now more switched on to the horrors of war.

But Julian Lewis, Chair of the UK’s defence committee told Business Insider that he’s now concerned about whether May will be able to properly fund the military after the NHS pledge.

"I am not won over … by this jargon of calling it a 'tier one' military power… What I’m much more concerned about is whether Theresa May will be able to give defence the money it needs," he said, citing a "whole" of over £4.9 billion in the defence budget.

May’s comments will not lead to definitive action to pair down the military, but are a clear sign of the direction of travel said Ripley.