Two environmental activists in their 80s attacked on Friday the casing of the historic Magna Carta document at London's British Library, causing damage to the glass case but leaving the document unscathed.

Anglican priest Sue Parfitt, 82, and retired teacher Judy Bruce, 85, hammered on the glass case then glued themselves to it, the environmental group Just Stop Oil said.

They also held a sign which read: "The government is breaking the law."

How did the activists justify the attack?

In a statement released by Just Stop Oil, Parfitt said Magna Carta was "rightly revered, being of great importance to our history, to our freedoms and to our laws."

But, she added, there would be "no freedom, no lawfulness, no rights, if we allow climate breakdown to become the catastrophe that is now threatened."

London's Metropolitan Police said the pair were arrested, after the library's security team intervened to prevent further damage. The Treasures Gallery was temporarily closed on Friday until further notice.

The climate action group and its members have targeted several high-profile events and artifacts in the UK, with the aim of raising environmental awareness and campaigning against the reliance on fossil fuels.

The Magna Carta was first issued in June 1215. It is revered as among the most important documents in the world for being an essential precursor for modern democracy, justice and the rule of law.

It was the first document to put into writing the principle that the king and his government were not above the law.

rmt/lo (AFP, AP)