Russian oligarch Boris Berezovsky, who was found dead at his Surrey home last week by a bodyguard, has been reported as having had a deep relationship with Israel, including a period in which he held dual Russian-Israeli citizenship.

Mr Berezovsky, born in Moscow in 1946 to a Jewish civil engineer and a mother with Jewish roots, was said to have become an Israeli citizen in the 1990s. He gave it up in the face of strong attacks by the Duma, the Russian parliament.

The oligarch built up a huge fortune as one of the group of businessmen who took control of state assets during the period of Perestroika and the collapse of the Soviet Union.

He acquired oil businesses, car showrooms and television stations and became one of the richest and most influential men in Russia during the presidency of Boris Yeltsin, with whom he had a warm relationship.

However, he fell out with President Vladimir Putin and, in 2003, fled to Britain, where he was given political asylum. Once resident in the UK, he loudly criticised Mr Putin and the Kremlin.

The death of Mr Berezovsky, a friend of Russian journalist Alexander Litvinenko, who died after being poisoned with radio active material, has been described by police as “unexplained”, although there were reports that he had committed suicide. He had recently been to Israel for medical treatment.

Mr Berezovsky’s fortune was diminished last year when he lost a multi-million pound High Court case against fellow Russian Jew Roman Abramovich and was ordered to pay £35 million in legal costs.