The day a letter bomb exploded inside 10 Downing Street with Margaret Thatcher inside

Margaret Thatcher PM pictured outside Downing Street, London, 30th November 1982. Prime Minister leaving Downing Street after one of her staff, office manager Peter Taylor, was injured after opening a letter bomb, fire bomb. Letters from a group called the Animal Rights Militia, ARM, were in the Downing Street package. (Photo by Andy Hosie/Daily Mirror/Mirrorpix/Getty Images)
Prime minister Margaret Thatcher outside 10 Downing Street on 30 November 1982, the day a letter bomb went off there. (Getty Images)

This article is part of Yahoo's 'On This Day' series

A letter bomb posted to 10 Downing Street exploded on this day 39 years ago.

On 30 November 1982, Margaret Thatcher was in her study at the prime minister’s residence when the device went off.

The letter bomb was in a package with letters from a group called the Animal Rights Militia - the parcel was addressed to Mrs Thatcher.

Her office manager, Peter Taylor, suffered burns to his hands and face when the device went off as he was holding it.

Remarkably, he was discharged from nearby Westminster Hospital after just a few hours and returned to work.

Margaret Thatcher at the Conservative Party Conference in 1983. In 1975 she was the first woman Party leader and in 1979 the first female prime minister in British politics. She resigned in 1990. (Photo by © Hulton-Deutsch Collection/CORBIS/Corbis via Getty Images)
Margaret Thatcher was in her study when a letter bomb ignited at 10 Downing Street in November 1982. Getty Images)

Police said later that the device was made with gunpowder, and had been designed to burn rather than explode.

The bomb was in a padded envelope addressed to the prime minister, which immediately aroused suspicions.

MORE FROM THE 'ON THIS DAY' SERIES:

President Nixon seals legacy with famous 'I am not a crook' speech

When Donald Trump caused 'the biggest political upset in history'

How the fall of the Berlin Wall helped end the Cold War

The day Osama bin Laden accepted responsibility for 9/11

Four other bombs were sent to political figures that day.

Labour leader Michael Foot, Social Democratic Party leader Roy Jenkins, Liberal Party leader David Steel and Home Office minister Timothy Raison were all sent letter bombs.

The four other letter bombs were intercepted and defused at the House of Commons, the Metropolitan Police said.

Thatcher told the House of Commons after the incident during Prime Minister’s Questions: “Letter bombs anywhere are most distressing and I’m afraid we are all vulnerable.

“From time to time MPs have received them. We have to take even more care in the future.”

Office workers at Number 10 thought the parcel looked suspicious and passed it to Taylor, 54, who was looking at it when it exploded.

Scene outside Downing Street, London, 30th November 1982. The Prime Minister, Margaret Thatcher, has left to the building due to security alert after one of her staff, office manager Peter Taylor, was injured after opening a letter bomb, fire bomb. Letters from a group called the Animal Rights Militia, ARM, were in the Downing Street package. (Photo by Andy Hosie/Daily Mirror/Mirrorpix/Getty Images)
The scene outside Downing Street, London, on 30 November 1982 after a letter bomb exploded and injured a member of staff. (Getty Images)
Scene outside Downing Street, London, 30th November 1982. The Prime Minister, Margaret Thatcher, has left to the building due to security alert after one of her staff, office manager Peter Taylor, was injured after opening a letter bomb, fire bomb. Letters from a group called the Animal Rights Militia, ARM, were in the Downing Street package. (Photo by Andy Hosie/Daily Mirror/Mirrorpix/Getty Images)
A police officer outside 10 Downing Street after a letter bomb addressed to prime minister Margaret Thatcher exploded. (Getty Images)
Downing Street, SW1, City of Westminster, London, 30th November 1982. (Photo by Andy Hosie/Daily Mirror/Mirrorpix/Getty Images)
A picture from Downing Street on the day a letter bomb exploded at Number 10. (Getty Images)

The force said the letter bomb addressed to Thatcher contained a note from the Animal Rights Militia claiming responsibility.

Read more: Boris Johnson ‘aims to beat Thatcher’s 11 years in office’

Police said the group was unknown to them.

It dismissed a claim to a radio station in Belfast that the letter bombs were sent by the Irish National Liberation Organisation.

Thatcher was in her private officer preparing for her PMQs at the time the device went off.

“We are keeping an open mind, but the fact that we have had this letter from the Animal Rights Militia must be kept in mind,” a police spokesman said.

“We do not believe the INLA claim,” he said.

A spokesman for the prime minister said she was “far away” when the blast occurred in another part of the building.

Read more: Conservatives criticise 'hateful' portrayal of Margaret Thatcher in 'The Crown'

The letter bomb was delivered just a week after an incendiary device was sent to industry secretary Patrick Jenkin by the Scottish National Liberation Army.

It was believed the group that sent the letters were angered at the British government’s attempts to block a European ban on imports of seal products.

Police said all of the letter bombs were part of the same batch.

Taylor’s eyes weren’t damaged because he was wearing glasses at the time. He was taken to hospital in the prime minister’s personal Jaguar car but left a few hours later.

Thatcher visited Taylor twice during the day to check on his health and wished him an easy day.

British Prime Minister Margaret Thatcher and her husband Denis (1915 - 2003) leave the Grand Hotel in Brighton, after a bomb attack by the IRA, 12th October 1984. They and many other politicians were staying at the hotel during the Conservative Party conference, but most were unharmed. (Photo by John Downing/Getty Images)
Prime minister Margaret Thatcher and her husband Denis leave the Grand Hotel in Brighton after a bomb attack by the IRA on 12 October 1984. (Getty Images)
The Grand Hotel in Brighton, after a bomb attack by the IRA, 12th October 1984. British Prime Minister Margaret Thatcher and many other politicians were staying at the hotel during the Conservative Party conference, but most were unharmed. (Photo by John Downing/Getty Images)
The Grand Hotel in Brighton after a bomb attack by the IRA on 12 October 1984. (Getty Images)
A white van is engulfed in flames at Whitehall, London, after a mortar bomb attack on Downing Street.   (Photo by PA Images via Getty Images)
A white van is engulfed in flames at Whitehall, London, after a mortar bomb attack by the IRA on Downing Street in 1991. (Getty Images)
A white van burns outside the Banqueting House in Whitehall after an attempted mortar bomb attack on Downing Street.   (Photo by PA Images via Getty Images)
A white van burns after an attempted IRA mortar bomb attack on Downing Street in 1991. (Getty Images)

Less than two years later, on 12 October 1984, Thatcher narrowly escaped from the IRA bombing of the Grand Brighton Hotel during the Conservative Party conference, which claimed the lives of five people, including Tory MP Sir Anthony Berry.

On 7 February 1991, the IRA carried out a mortar attack on Downing Street in an attempt to assassinate prime minister John Major and his war Cabinet, who were meeting to discuss the Gulf War.

One of the mortar shells exploded in the back garden of Number 10, but because of bomb-resistant windows, none of the Cabinet were hurt. Four people did suffer minor injuries, including two police officers.

Watch: From Thatcher to May, prime ministers' resignations