Blair began work as a consultant to Kazakh President Nursultan Nazarbayev a month before the incident, according to an investigation by the Times.

The former PM has come under scrutiny for his work with Nazarbayev, who has been accused of running an authoritarian government and committing widespread human rights abuses.

Since leaving Downing Street in 2007, Blair is believed to have engaged in a string of questionable business deals with repressive regimes around the world, including Saudi Arabia and China.

The oil workers in Mangystau region were killed by police in December 2010, in what has become known as the Zhanaozen massacre. Their strike had been declared illegal in local courts.

Seven months later, Blair apparently advised Nazarbayev how to present the deaths when the president gave a speech at the University of Cambridge.

The former PM told Nazarbayev to say the deaths, “tragic though they were, should not obscure the enormous progress” the country had made, according to the Times.

Prior to this Nazarbayev had said: “There was a very violent confrontation and people died. It was a terrible thing, but nearly all the people associated with that have moved on or changed.”

In 2014, the former PM’s consultancy firm, Tony Blair Associates (TBA), was given a two-year contract by the Mangystau region to transform its economy.

Although the contract expired last summer, the Times reports Blair visited the region again on September 18 to advice the local government on “economic reforms.”

Mangystau Governor Alik Aidarbayev was previously chief executive of KazMunaiGaz (KMP), the oil company whose workers were massacred during their strike action.

Aidarbayev was appointed chief executive after the killings, when he “admitted guilt” and promised to pay more attention to industrial relations.

Hugh Williamson, director of the European and Central Asia division of Human Rights Watch, criticized the former prime minister for doing business with Kazakhstan.

“Mr Blair has said publicly that he sees his mandate in Kazakhstan as to do good for the country rather than just to raise money for his own operations, so we feel it’s appropriate and necessary for him to be raising human rights issues,” he said.

“We’ve got no evidence he has been doing so [and] we see the danger if he doesn’t do so as whitewashing the image of the government.”

A spokeswoman for Blair said TBA’s work in Mangystau involved “no comms [communications] element.”

She said he was hired to “help build capacity to attract investment and improve accountability as Mangystau sought to deliver better services for its citizens.”

Tony Blair Associates has also been linked to a Saudi Arabian oil company founded by the son of Saudi Arabia’s late King Abdullah.