A leaked memo appears to show the Saudi Arabian government knew the mass execution of 47 people would spark an angry backlash and ordered its security services to be on full alert before going ahead, The Independent can reveal.

The letter was issued by the head of Riyadh’s security services and ordered forces across the conservative kingdom to cancel planned holidays from 31 December onwards and exercise “maximum precaution” until further notice.

The document was leaked by Saudi human rights campaigners and has been seen by The Independent. It seems to have been sent to unit chiefs in the regions where the executions took place and marked “very urgent”.

Saudi Arabia carried out the executions on 2 December, and the decision to kill a prominent Shia cleric in particular has led to diplomatic fallout across the Middle East.

In pictures: Protests around the world over Saudi executions Show all 7 1 /7 In pictures: Protests around the world over Saudi executions In pictures: Protests around the world over Saudi executions Protests around the world over Saudi executions Iranian and Turkish demonstrators hold pictures of Shiite cleric Sheikh Nimr al-Nimr as they protest outside the Saudi Embassy in Ankara, Turkey, In pictures: Protests around the world over Saudi executions Protests around the world over Saudi executions Kashmiri Shiite Muslims, carrying a placard with the portrait of Sheikh Nimr al-Nimr, shout slogans during a protest in Srinagar, Indian controlled Kashmir, In pictures: Protests around the world over Saudi executions Protests around the world at Saudi executions Indian police used tear smoke and rubber bullets to disperse Shiite Muslims who were protesting after Saudi Arabia announced the execution of Shiite cleric Sheikh Nimr al-Nimr on Saturday along with 46 others, including three other Shiite dissidents and a number of al-Qaida militants. In pictures: Protests around the world over Saudi executions Protests around the world over Saudi executions Shane Enright, Global Trade Union Advisor for Amnesty International, addresses demonstrators as they protest outside the Saudi Embassy in London, following Saudi Arabia's execution of 47 prisoners in one day, including a top Shiite cleric In pictures: Protests around the world over Saudi executions Protests around the world over Saudi executions Iranian protestor burn pictures of a member of the Saudi royal family in front of the Saudi Arabia embassy in Tehran, Iran, 02 January 2016. Protesters have stormed the Saudi embassy building in the Iranian capital of Tehran early Sunday amid backlash over the execution of a prominent Shiite cleric. Flammable substance was seen thrown at the building as protests gained steam over the execution of Sheikh Nimr al-Nimr. Reports states, protesters taking down a Saudi flag and burned the building. In pictures: Protests around the world over Saudi executions Protests around the world over Saudi executions Shiite Muslims hold placards with pictures of Saudi Shiite cleric Sheikh Nimr al-Nimr, whose execution in Saudi Arabia was announced Saturday, during a demonstration to condemn his execution, Sunday, Jan. 3, 2016 in Peshawar, Pakistan In pictures: Protests around the world over Saudi executions Protests around the world over Saudi executions A Kashmir Shiite Muslim shouts slogan from Indian police vehicle after he was detained during a protest in Srinagar, the summer capital of Indian Kashmir,

The backlash has included a shoot-out with police in the home village of the cleric Sheikh Nimr al-Nimr, as well as the ransacking of the Saudi embassy in Shia-dominated Tehran.

And the human rights group Reprieve, which was passed the Saudi government memo by local campaigners, said it showed just how “politically-motivated” the mass executions were.

Maya Foa, head of the death penalty team at Reprieve, said: “This letter shows the level of preparation the Saudi authorities went to ahead of Saturday, having predicted the outrage that would follow their politically-motivated executions of protesters.

“If the Saudi government really wants to prove itself on the international stage, it must stop torturing and executing protestors, and commit to fair, transparent trials.”

Since a large group of protesters invaded the Saudi embassy in Tehran on Saturday night, the Saudi government has painted itself as the victim of an unwarranted interference into its internal affairs, recalling its ambassador and severing all diplomatic channels.