Important details have been released of who was behind a mysterious business deal that ended a bitter dispute over gas prices between Russia and Ukraine at the start of the year. This report from Mark Gregory:

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The company RosUkrEnergo was awarded a monopoly of Ukraine's major energy source. It is half controlled by Gazprom, the Russian energy giant, that was always clear, but who were the other investors? This week the mystery has been cleared up. They are two Ukrainian businessmen, the main one being a forty year old tycoon named Dmytro Firtash.

After concealing his identity for months, he's now talking to Western financial newspapers. And he says he is considering raising millions of dollars by a share flotation on the London stock market. He broke cover after his name was mooted in the Russian newspaper Isvestia, which incidentally is owned by Gazprom. Mind you, Gazprom claims it didn't know who he was until very recently, even though he is their business partner.

Mr Firtash was not born to wealth - his father was a driver, his mother a cook. He worked as a fireman after failing to get into university in the former Soviet Union, and then made his fortune trading gas from Turkmenistan. The story has emerged a day after Moscow accused the West of double standards in its dealings with Russian energy companies.

Mark Gregory, Business Reporter, BBC

Listen to the words

a murky deal
a suspicious arrangement

cloak and dagger
secret

a row
an argument, a dispute

a monopoly
total business control over

concealing his identity
hiding who he was

broke cover
stopped hiding

mooted
suggested

was not born to wealth
was not born in a family which had money

emerged
came out, became public

double standards
saying one thing but doing another