How an oil tycoon became 'the poorest man in the world'

When I last saw Boris Berezovsky he was surrounded by a phalanx of dark suited body guards and would sweep up to court in a presidential style convoy of Range Rovers, accompanied by a massive team of London's most expensive lawyers.

That was at his court case against Roman Abramovich in 2012 - the most expensive private case in British history, when Mr Berezovsky could still lay claim to be being among Russia's richest and most powerful oligarchs.

Today at the inquest into his death, family and employees described how losing that court case was a turning point that initiated a dramatic change in his fortunes.

Afterwards Mr Berezovsky considered himself to be financially ruined. He felt his influence as a power broker in Russia was lost. His partner left him and initiated a legal proceeding for a share of what was left of his money.

Even his huge security detail dwindled to a single bodyguard. That bodyguard told the inquest today that Mr Berezovsky would tell him "I'm not a billionaire. I'm the poorest man in the world".

Crucially for those trying to understand why he ended up dead in a Surrey bathroom with a ligature around his neck - the court case, his family say, had also made him clinically depressed.

At the inquest his ex wife, daughters, bodyguard and psychologist all testified that he was taking anti-depressants in the months leading up to his death and had regularly talked about suicide.

The Detective Inspector in charge of the investigation into his death concluded that there was no criminal activity that contributed to his death.

However he did admit that there were three outstanding issues in the investigation which were puzzling. Police were unable to identify a fingerprint in the bathroom where he died, nor could they trace a stranger seen by a witness near the house two days before.

And perhaps most odd, given Mr Berezovsky's friendship with Alexander LItvinenko who was assassinated with polonium, two radiation warning devices were activated when emergency services arrived at the scene.

Subsequent tests however, ruled out any radioactive substance at the house.

At the time of his death, suicide was considered by many, to be the least likely explanation. After all, here was a man who had survived previous assassination attempts, whose friends died in mysterious circumstances and who for years had been an outspoken critic of the Kremlin.

His family, friends and his doctors have testified that, he talked of taking his own life, but none of those who knew him best, thought he was serious.

The inquest will continue on Thursday with evidence from his eldest daughter and new and 'potentially significant' testimony from a forensic pathologist hired by the family.