A 1,500-strong force of EU troops was on manoeuvres in Britain last week – despite Armed Forces Minister Penny Mordaunt warning that plans for a 'Euro army' hatched in Brussels and Berlin are a 'huge concern'.

Ms Mordaunt only had to look as far as Salisbury Plain, Britain's largest military training ground, to see that their tanks and vehicles – some emblazoned with the EU flag – are already on our lawn, as our exclusive photographs show.

They were taking part in what is thought to be the biggest EU military exercise in the UK. And in a move that might cause further concern for Brexiteer Ms Mordaunt, the joint war games played out by an 'EU Battle Group' represent a stepping up of plans to mount a European force capable of rapid deployment to foreign shores.

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Penny Mordaunt only had to look as far as Salisbury Plain, Britain's largest military training ground, to see that 'Euro army' tanks and vehicles are already on our lawn

EUBG: The European Union Battle Groups consist of three 1,500-troop rapid reaction forces, directed by the EU's Council of Ministers, and designed to respond to security crises

Even as the columns of troops from Sweden, Latvia, Finland, Lithuania and Ireland rumbled across the English countryside, the Government was forced to reiterate David Cameron's opposition to a European army.

'The Prime Minister has repeatedly made clear that the UK will never be a part of an EU army,' said a spokesman.

SO WHAT ARE THE EUROPEAN UNION BATTLE GROUPS? Three 1,500-troop rapid reaction forces, directed by the EU's Council of Ministers, and designed to respond to security crises. Austrian Lieutenant General Wolfgang Wosolsobe is in command. Advertisement

'We will oppose any measures which would undermine member states' military forces.'

That will come as no comfort to Eurosceptics suspicious of the German government's revived enthusiasm for a European army, to be set out in July.

The publication of the plans – which outlines steps to 'gradually co-ordinate Europe's patchwork of national militaries' – was postponed until after the EU referendum on June 23.

The 1,500-strong EU Battle Group on Salisbury Plain was joined by troops from 2nd Battalion, the Yorkshire Regiment, and 4th Infantry Brigade, as they planned and executed a 'fictitious peace support operation'.

Troops were involved in rapid movements, maintaining public order and peacekeeping in rural and urban environments.

While a British Brigadier is in charge of the force during the UK's period of command, he takes his orders from Brussels, not from the UK's operational headquarters.

Tactical decisions, such as the rules of engagement for the EU Battle Group, are decided by the Foreign Affairs and Security Council of the European Union.

The EU has three Battle Groups and the one deployed to the UK is a 'light force' – using armoured patrol vehicles such as Humvees and the RG-32M 'Scout'.

Don't panic: A British solider manning a machine-gun keeps a close eye on the EU Battle Group operation

Ms Mordaunt reacted furiously earlier this month to a call from Joseph Daul, the French president of the centre-Right European People's Party, to form a Euro army.

Mr Daul said in a speech: 'Today more than ever, the peace of our continent cannot be safeguarded without a common and functional security union, including a European army.'

Miss Mordaunt said: 'This is proof of the European Union's plan to create a Euro army – and it is dishonest for the In campaign to claim otherwise.

'The prospect of having our security policy dictated by Brussels is a huge concern – and makes a mockery of the claim Britain is stronger in the EU.'