STALYBRIDGE, ENGLAND - JUNE 28: Soldiers from 4th Battalion Royal Regiment Scotland arrive at Swineshaw reservoir in Stalybridge on June 28, 2018 in Stalybridge, England. Around 100 soldiers are to be deployed to help the Fire and Rescue service tackle the large moorland fire above Stalybridge. Anthony Devlin/Getty

The UK and its NATO allies would lose to Russia if they went to war as they are woefully outgunned, a leading defense think tank says.

The Royal United Services Institute (RUSI) said on Wednesday the UK is „comprehensively outgunned and outranged“ by Russia.

The London-based think tank notes all-out-war with Russia is „unlikely,“ but says the „UK’s ground forces need to increase their deployable firepower if they are to maintain a credible warfighting capability.“

Russia has six times more military personnel than the UK. The UK has 215 nuclear weapons, compared with Russia’s 6,800.

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UK and NATO forces will be decimated in a war with Russia because they can’t compete in terms of firepower, a leading defense think tank has said.

A Royal United Services Institute (RUSI) report said the UK will be „comprehensively outgunned and outranged“ in a military conflict with Russia, „leaving enemy artillery free to prosecute fire missions with impunity.“

This will „lead to the defeat of UK units in detail,“ the report, shared with media ahead of publication on Thursday, said.

„Whatever platforms are developed and procured, it is clear that the UK’s ground forces need to increase their deployable firepower if they are to maintain a credible warfighting capability.“

putin army Maxim Shemetov/Reuters

„At present, there is a risk that the UK — unable to credibly fight — can be dominated lower down the escalation ladder by powers threatening escalation.“

The report notes that all-out-war with Russia is „unlikely.“

It is also highly unlikely that the UK and its European allies in NATO would ever be left to fight Russia alone. Under NATO rules, the US is obligated to intervene if any other NATO nation is attacked by a foreign power. While US President Donald Trump has repeatedly threatened to pull out of the coalition, he has yet to follow through on that threat.

The report criticised NATO forces, saying they „have tended to significantly underestimate the quantity of firepower needed to enable ground manoeuvre without prohibitive casualties, when fighting in complex terrain.“

The British Army has around 900 troops stationed on rotation in Estonia and Latvia, which border Russia, as well as nearby Lithuania and Poland. The British Army is comprised of 83,500 troops, which is dwarfed by the 350,000-strong Russian Ground Forces.

The UK has 215 nuclear weapons, compared with Russia’s 6,800, according to the Arms Control Association.

Britain’s armed forced have shrunk every year for the last nine years, amid a struggle to recruit new troops.

However, the UK has recently built two aircraft carriers, costing a combined £6 billion ($7.7 billion), and spent £9 billion ($11.6 billion) on 48 F-35 fighter jets.

Britain’s Ministry of Defense said in its response to the paper that: „The UK does not stand alone but alongside its NATO allies, who work closely together across air, sea, land, nuclear and cyber to deter threats and respond to crises.“

„As the largest NATO defence spender in Europe, the UK’s armed forces are well equipped to take a leading role in countering threats and ensuring the safety and security of British people at home and abroad.“