As political infighting escalated in the weeks leading up to Prime Minister Sir Keir Starmer’s resignation last month, the Foreign Office sent a WhatsApp message to Britain’s ambassadors around the world.

What did overseas governments make of the turmoil, the department wanted to know. A key theme, according to people familiar with the exchanges on the group chat, was that, in the view of some other nations, the UK had become too “inward-looking” and “insular”.

As the UK’s sixth leader in 10 years heads for the exit, the comments confirmed what officials suspected: not only has much of the country’s military firepower withered but its image across the world is also much diminished.

In the past, even when the UK’s defence spending has ebbed, the country could rely on its less tangible sources of international influence, aided by the dominance of the English language and the role of multinational institutions in which Britain has played an outsized role, such as the UN.

But now the UK’s hard and soft power have both hit postwar lows, hit by factors ranging from budget constraints to the decision 10 years ago to leave the EU and Donald Trump’s bid to remake the international order.

Many Nato countries have struggled to return defence spending to cold war levels since Russia’s invasion of Ukraine. Even so, the decline of Britain’s armed forces stands out. All branches of the services — the army, navy and air force — are either half the size or less than half the size they were at the end of the cold war.

“There is nothing in the cupboard, essentially,” says General Sir Richard Barrons, former commander of the UK’s Joint Forces Command.

Cuts to Britain’s international aid budget and reduced funding for organisations that boost the UK’s cultural influence abroad, such as the BBC World Service and British Council, have also damaged Britain’s international clout, critics say.

This week, in an essay for the think-tank Chatham House, foreign secretary Yvette Cooper wrote that the foreign policy mistakes of successive governments had left the nation “more exposed”.

Under-investment in defence, slipping into over-reliance on China for crucial supply chains, complacency towards important international relationships and damaging a “reputation for seriousness” thanks to Brexit were among the errors she listed.

Britain is now worse equipped to adapt to or shape a fast-evolving new global order, officials and analysts say, just as former Greater Manchester mayor Andy Burnham — who has little foreign policy experience of his own — prepares for July 20, when he is likely to become prime minister.

Olivia O’Sullivan, director of the UK in the World programme at Chatham House, notes the “deep underlying strategic challenges” facing the UK.

“Our closest security partner for decades, the US, is becoming volatile,” she says. “For a decade we’ve had an uncertain relationship with our closest economic partner, our closest market, the EU. We’re still trying to get a grip on how we manage China’s growing dominance and influence.”

She adds: “It’s now urgent and apparent that the guardrails for British foreign policy are wobbling.”

Not fit for service

The reduced circumstances of the UK’s armed forces are the product of the period of relative peace in the west since the cold war.

The absence of an existential threat post-1989 led to a “hollowing-out process”, says Barrons, the former head of Joint Forces Command.

“You steadily reduce money for training and logistics and other forms of support services and infrastructure maintenance,” he adds. “And so the point the armed forces are at now is not just a massive reduction in size, it’s a massive reduction in readiness.”

For much of the 21st century, the UK military’s operations were chiefly counterinsurgencies alongside the US.

This shaped today’s force, which is accustomed to fighting low-intensity wars and specialises in expeditions in far-flung corners of the world. In Iraq, UK forces were plagued by shortages and even came to be known as “the borrowers” by US troops.

“We have been the beneficiaries for decades of an incredibly generous security guarantee from the United States. But my strong view is that we have been infantilised by it,” Sir Alex Younger, the former chief of MI6, said in an interview with The Economist shortly before his death last month.

Russia’s invasion of Ukraine shattered the complacency. Yet the UK has continued to tumble down various Nato league tables, slipping to 12th place among the alliance’s 32 members for defence expenditure as a proportion of GDP last year.

Britain is now on track to spend just 2.7 per cent of GDP on defence by 2030, despite a commitment to Nato to reach 3.5 per cent by 2035. France is in a similar situation to Britain and both are nervous about Germany, which has deeper pockets, becoming the pre-eminent European power in Nato.

The spectacle of the Royal Navy needing roughly a week to dispatch a single Type 45 destroyer from England’s south coast prompted derision during the US-Iran war.

Once the destroyer, the HMS Dragon, finally arrived in Cyprus, it suffered an additional humiliation when a technical issue required it to dock.

Former military officials, who speak on behalf of serving comrades, express their frustration with the state of the armed forces. While the UK has provided generous military aid to Ukraine, it would struggle to maintain peacekeeping troops in the country were they ever required, according to General Lord Richard Dannatt, a former head of the British Army

The Royal Navy has been hit hard in recent decades across all of its operations except the nuclear deterrent, which remains a valuable strategic asset. Much of the equipment budget went to the army up until 2020. “There simply has not been enough investment in the navy, and unfortunately it shows,” says retired Rear Admiral Jon Pentreath.

Restocking the navy — which must defend the north Atlantic shipping lanes from Russian submarines in case of war — is a tall order. The fleet now has just 13 frigates and destroyers, down from 59 four decades ago.

But the army is also in dire straits. While Russia is firing up to 10,000 artillery shells a day in Ukraine and fielding thousands of drones daily, senior officers at a recent military exercise admitted that, instead of thousands of drones per day, Britain would have only hundreds, lasting less than a week in a high-intensity conflict.

Despite billions of pounds poured into procurement programmes, the UK’s efforts at military transformation have lagged. The Ajax armoured fighting vehicle, intended to become the backbone of the army, is eight years behind schedule, cost more than £6bn and made soldiers ill during trials because of excessive vibration and noise.

Agonised wrangling between the Ministry of Defence, which warned of insufficient funding, and the Treasury and Downing Street led to repeated delays to the UK government’s defence investment plan, which Starmer finally unveiled last week.

Ultimately Starmer promised to provide £15bn over the next four years, about half the £28bn funding gap defence officials identified last year — but he admitted that £4.7bn of the new package was unfunded.

The remaining £10.3bn is intended to largely come from cuts — but so far the UK government has only been able to specify a handful of cases in which it would make savings.

The UK will struggle to fund the rearmament envisaged in a strategic defence review last year, which called for £68bn in new equipment, including warplanes, a tranche of F-35 fighters and up to 12 nuclear-powered attack submarines at an estimated £2bn-£3bn per unit.

Britain still depicts itself as a major military power. At the Nato summit in Ankara this week, it positioned itself as the leader of a new initiative involving about a dozen European allies spending £37bn to develop “deep precision strike” missiles over the next decade. Starmer was also at pains to stress Trump thanked Britain at the meeting for being the second-largest Nato spender in cash terms over the past decade.

But in European diplomatic and military circles, the UK is sometimes accused of talking up big plans without allocating sufficient resources to back up its grand rhetoric.

In particular, the relatively modest scale of the planned increase in the country’s military investment could pose a problem for Europe’s efforts to look after its own security as the US reduces its own presence on the continent.

It is also set to be one of the enduring headaches for Burnham’s likely new administration.

Treasury officials believe the Ministry of Defence has a poor record of controlling costs, and throwing more money at defence industries before they can scale up could prove inflationary. Since the war in Ukraine started, for example, the cost of artillery shells has tripled, while production has barely nudged up.

“There’s narrow room for the new [equipment], because we’re not going to borrow and we’re not going to tax at this stage,” says one official. “Therefore, for defence to get more money, it’s a zero-sum game. For us to get more money, others must lose.”

Soft power runs short

The UK has traditionally drawn its soft power from sources as diverse as Britain’s cultural exports and its reputation for upholding democratic values, as well as the country’s seat at the table in forums setting worldwide rules and standards.

But in the past 10 years, this too has been in relative decline, with aspects of British influence taken for granted — if not actively squandered — by successive governments. Tighter visa restrictions have led to a fall in the number of overseas postgraduate researchers coming to the UK, while cash-strapped British universities have closed courses and reduced staff.

“Britain’s soft power has been hollowed out,” says one senior UK official.

Over the past 20 years governments have cut back on funding for high-profile assets such as the BBC World Service and the British Council, which provides other countries with development assistance and seeks to foster cultural relations.

Critics of those moves say both institutions offer relatively cheap and good-value tools for boosting UK influence abroad — sources of soft power few other countries have previously rivalled.

But countries including China, Russia and India have increasingly channelled significant resources into their own diplomatic, cultural and educational programmes internationally.

Both Labour and Conservative governments were once proud of the UK’s status as a major donor country and its compliance with UN development goals.

But in 2020, Boris Johnson’s government merged the Department for International Development into the Foreign Office — supposedly, it argued at the time, to give the UK “even greater impact and influence on the world stage” by mobilising the country’s “aid budget and expertise, to safeguard British interests and values overseas”.

Since then both Conservative and Labour governments have more than halved foreign aid as a percentage of gross national income from 0.7 per cent to a forecast 0.3 per cent in 2027.

The aid sector argues such cuts are a false economy, failing to prevent conflicts at source or stem the flow of refugees from fragile states — as well as retreating from the country’s global role.

In a sign of what appeared to be the UK’s weakening convening power, when Cooper, the foreign secretary, announced a new UK-led coalition to tackle violence against women and girls at a London conference in May, only seven other nations were announced as founding members.

One official insisted the plan had always been to launch it with a small group of founding members then to seek expansion.

“Chaotic politics, bad, alienating decisions like leaving the EU, stagnant economic growth, and under-investment in a lot of core institutions . . . have all taken a toll on the UK,” says Mark Leonard of the European Council on Foreign Relations, a think-tank.

Morale within the Foreign, Commonwealth and Development Office is weak as it undergoes a major restructuring and headcount reduction. Some teams are losing more than 25 per cent of personnel. Almost all officials have been forced to reapply for their jobs.

Leonard adds that the contrast between the UK’s full-throated backing for Ukraine’s struggle against Russia and its evolving stance on the Israel-Gaza war has created a perceived hypocrisy.

Part of Britain’s waning influence is beyond its control. Some of the international institutions in which it has wielded power and global issues on which it has shown leadership are receding in importance.

“The UN is in decline, the Commonwealth is in decline. The UK’s genuine leadership role and commitment on climate is less valuable than before,” says Ben Judah, a foreign policy specialist and former Labour adviser.

“We are also losing influence because the west is losing influence. The western alliance is fragmenting, as the Chinese authoritarian axis is deepening,” he adds.

‘Our allies are very cynical’

Starmer’s stint in office has partly been defined by the time he has dedicated to foreign affairs, giving rise to the nickname “Never Here Keir”.

He has worked closely with other European states, especially in helping to manage the rift between the US and Ukraine, and those close to him prize his record as a deft “chief diplomat”.

But the outgoing UK prime minister has not set the agenda in the fashion of Canadian Prime Minister Mark Carney, who at Davos in January appeared to criticise Trump and called for greater co-operation among the world’s middle powers — or indeed French President Emmanuel Macron.

“Starmer hasn’t articulated a narrative as powerful,” says one senior British diplomat.

Critics add that Starmer’s bid to maintain close ties to Trump in an effort to win influence and favourable economic terms for Britain has not wholly paid off. Despite his charm offensive — which involved inviting the US president to make a second state visit to the UK — Trump has treated him with borderline scorn in recent weeks.

The UK had no obvious sway in restraining Washington in its strikes against Iran.

As for the prime minister’s likely replacement, Burnham’s foreign policy instincts remain something of a mystery. As mayor of a northern British city for the past nine years, his foreign interventions have been few and far between.

Some Labour officials are anticipating a high degree of continuity on issues such as Ukraine, thanks to the willingness of Jonathan Powell, Starmer’s national security adviser, to remain in post at least for a transition period.

But Burnham’s approach to Brussels and whether he will pursue a more profound reset of UK-EU relations than Starmer is unclear.

Only last autumn Burnham told the annual Labour conference: “I want to rejoin the EU. I hope it happens in my lifetime.”

However, during his campaign in the by-election last month that took him back to parliament, Burnham insisted he was “not proposing that the UK considers rejoining the EU” and stressed his respect for the result of the 2016 referendum that voted to leave the bloc.

After that vote a decade ago, the UK sought to project its influence through a “Global Britain”, which emphasised the country’s interests and activities far beyond Europe.

Professor Michael Clarke of King’s College London says the Labour government was right to pivot away from that pitch — which he labels “foolish and unsustainable” — to focus on the Atlantic and Nato.

But, Clarke says: “We have to make some really tough choices between welfare and warfare. We’ve got to address properly the state of Britain’s defences.”

Soft and hard power are not alternatives, he adds. “They’re complementary. And the sheer lack of defence resource means that all this leadership we offer to our European partners is made to look a bit thin in reality . . . Our allies are very cynical about us now.”