Margaret Thatcher secretly considered calling out the troops at the height of the miners’ strike amid fears union action could destroy her Conservative government, according to newly released files.
Government papers from 1984, released by the National Archives, show ministers were so concerned at the outbreak of a national docks strike while the miners were still out, they considered declaring a state of emergency.
Plans were drawn up for thousands of service personnel to commandeer trucks to move vital supplies of food and coal around the country.
It was probably the closest Mrs Thatcher came to defeat in her battle with the miners but the scheme was never implemented after the dockers’ action petered out after less than two weeks.
The epic, 12-month confrontation between the Conservative government and the National Union of Mineworkers (NUM) and its left-wing president Arthur Scargill was one of the defining episodes of the Thatcher era.
It saw some of the worst industrial violence the country had witnessed, with hundreds injured in brutal picket line clashes between police and miners, and ended in crushing defeat for the NUM.
From the outset both sides were clear there was more at stake than the plan by the state-owned National Coal Board (NCB) to close 20 loss-making pits which triggered the start of the strike in March 1984.
Mr Scargill declared the NUM was engaged in nothing less than a “social and industrial Battle of Britain” while at No 10, one official wrote it was “a unique opportunity to break the power of the militants in the NUM”.
By the summer both sides appeared locked in a lengthy war of attrition, until early July when the sudden escalation of a local dispute at Immingham docks into a national strike appeared to offer the miners the chance of a breakthrough.
In No 10 John Redwood, the head of the policy unit, warned the NCB’s position was “crumbling” but said that giving in to the unions would be “the end of effective government” in Britain.
“The Left’s aim is to pave the way for the ultimate defeat of the Government by destroying its policies and its credibility,” he wrote in a memorandum to Mrs Thatcher. “Its purpose is to oppose and destroy.”
On July 16, with the Ministry of Agriculture warning of panic-buying of food stocks if the docks strike took hold, Mrs Thatcher summoned a meeting of key ministers to discuss the declaration of a state of emergency under the Emergency Powers Act (EPA).
It was quickly agreed that an initial assessment that 2,800 troops could move 1,000 tons of goods a day using around 50 lorries was “far too low” for what was needed.
Ministers, however, were also nervous that calling out the Army could simply make matters worse, while some questioned whether the existing powers under the EPA were adequate.
“It was not clear how far a declaration of a state of emergency would be interpreted as a sign of weakness, nor to what extent it would increase docker support for the miners strike,” the minutes noted.
Nevertheless officials continued to dust off plans which suggested 4,500 military drivers and 1,650 tipper trucks - around 10% of the national stock - would be needed to keep coal supplies moving.
On July 18, the armed forces minister John Stanley reported the Ministry of Defence was reassessing its contingency plans.
“It was clear already that service manpower and plant could be provided from within Great Britain on a considerably larger scale than that provided for under previous plans,” he advised.
Three days later the dock strike was ended. But while the immediate crisis for the government appeared to be over, some ministers feared the struggle was not going their way.
Since 1981, ministers had been secretly preparing for the showdown with miners which many believed was inevitable - covertly building up coal stocks at Britain’s mainly coal-fired power stations to enable them to outlast a strike without disruption to electricity supplies.
However on July 25, in a letter marked “SECRET & PERSONAL”, trade and industry secretary Norman Tebbit wrote to Mrs Thatcher expressing concern that coal supplies were set to run out by mid-January.
“My concern is that, on our present course, I do not see that time is on our side,” he wrote.
“On present trends it will become clear sometime in the autumn to miners on strike that the end of the dispute is approaching, and they will be fortified in their resolve. My own guess is that we may come to that point as early as October.”
He concluded: “I have no wish to rock the boat, and believe it essential that we should continue to present our existing public face. But it is just as important that we should be utterly realistic among ourselves about what is actually going to happen.”
Assured, however, by her officials that power supplies could be maintained well into the following summer and beyond, Mrs Thatcher stuck doggedly to her guns.
The final crisis for the government came in October with a threatened walk-out by the pit deputies union, NACODS. Without the men responsible for pit safety, those mines which had refused to join the strike and had carried on working would have to close, once again threatening coal stocks.
The files show that worried officials drew up contingency plans to conserve supplies, including - chillingly for the Tories with memories of the 1970s - the imposition of a three-day working week.
But when the NACODS action was called off, it was clear the dispute with the NUM had reached a turning point, as disheartened miners began the slow drift back to work.
On November 20, the government’s daily coal report noted that since November 5, 10,442 men had returned to the pits.
“There can be no better evidence that Mr Scargill’s case is failing,” it declared.