Britain’s Defence Cash Gap: Investors Won’t Rescue a Broken System

RUSI’s paper gives the UK a hard defence-industry warning.

Ministers want more weapons, more innovation and more factory capacity, but the public purse is already under strain.

Private capital is being eyed as the extra fuel for Britain’s defence revival.

The catch is ugly: investors will not pour serious money into a sector where procurement is slow, signals are weak, risks are murky and government still behaves like an unreliable customer.

The UK wants wartime production energy with peacetime bureaucracy still in the way.

The money problem is real

Britain has promised to raise defence spending in line with NATO’s 3.5% of GDP target by 2035.

That sounds muscular, but it does not solve the immediate financing problem. New factories, expanded production lines, research and development, start-ups and supply-chain resilience all need serious capital now.

RUSI’s point is blunt: government spending will remain the main engine of defence growth, but it will not be enough on its own if Britain wants speed, scale and innovation.

Investors smell risk

Defence is suddenly fashionable again, helped by Ukraine, rising European demand and the scramble to rebuild Western stockpiles.

But enthusiasm is not the same as investability. Private investors want clearer demand, faster decisions, better market intelligence and confidence that good companies can actually win contracts.

At the moment, the UK system still makes too many promising firms look like bets on Whitehall mood swings rather than solid strategic investments.

Procurement is the choke point

The paper’s sharpest warning is about procurement.

If the Ministry of Defence wants more private money in the sector, it must buy faster and more openly from innovative firms. That means accepting more risk rather than hiding behind slow procedures that kill momentum before new technology reaches the field.

But this also needs political cover. Faster procurement will produce failures. Some projects will disappoint. RUSI argues that ministers must explain this honestly, instead of letting every failed bet become a scandal that scares the system back into caution.

Whitehall lacks market eyes

RUSI wants UK Defence Innovation to build a market insights and analysis unit drawing information from UKDI, DSTL, DE&S and other MoD bodies.

That sounds technical, but the problem is simple: the government does not know enough, quickly enough, about which firms could build strategic UK industrial strength.

Without better intelligence, promising companies can be missed, duplicated or left to chase money without a clear route into defence demand. Britain cannot scale what it cannot spot.

Capital needs coordination

The paper also calls for a defence investment coordination forum linking government with trusted private investors.

This is not about handing strategy to financiers. It is about making sure capital flows towards areas that matter for national security and UK industrial capacity.

If left purely to the market, investors will chase returns wherever they appear. If controlled too tightly by government, money may not move at all. The UK needs a middle channel – trusted, strategic and practical.

Security screening slows the deal

Investment controls are another brake.

Defence companies are sensitive assets, and the UK cannot let hostile or careless money gain access to critical technology. But repeated screening, uncertainty and long notification-to-decision timelines can raise transaction risk and weaken investor appetite.

RUSI’s answer is a certification regime for trusted defence investment funds. Vetted funds with structures that protect sensitive information and prevent undue influence could avoid repeated notifications.

That would keep security in place while cutting needless friction.

The innovation story is still too fragile

The UK wants defence start-ups, spinouts and regional industrial growth to power both national security and economic renewal.

But that ecosystem will not grow on speeches alone. Small firms need cash, patient customers, credible contracts and a route from prototype to production.

Late payments, long procurement cycles and weak demand signals can crush exactly the companies Britain says it wants to champion.

The reality check: Private capital follows confidence, not slogans.

RUSI’s warning is clear. Britain cannot simply announce a defence-industrial revival and expect investors to do the heavy lifting.

Private money can help build factories, scale new technologies and strengthen supply chains. But only if government fixes the pipes: procurement, communication, screening, intelligence and trust.

The UK wants more private capital in defence. First, it must become a customer worth backing.