Nikolai Glushkov, 68, was found strangled to death in his home on the day he was supposed to appear at court to fight a compensation claim

An exiled critic of Vladimir Putin was found strangled to death on the day he was due in court to fight a $99 million compensation claims, it has emerged.

Nikolai Glushkov, 68, was pursued 'to the bitter end' by lawyers acting for the airline Aeroflot, the High Court disclosed yesterday.

A judge yesterday ordered the firm to pay full costs, estimated at £5m, for what he considered to be politically motivated persecution by the Kremlin.

The court heard Mr Glushkov had to fight the case himself after running out of money for lawyers.

It was also revealed on Friday that:

The Metropolitan Police had identified a further 321 potential witnesses to Mr Glushkov's murder;

Law firm Pinsent Masons lost 'sight of any basic standard of decent and compassionate behaviour' in its pursuit of Mr Glushkov, according to a judge;

The Russian embassy said it was frozen out of the murder inquiry.

Mr Glushkov's friend Boris Berezovsky was found dead in his Berkshire home in 2013 and the death of another of their circle, Badri Patarkatsishvili, is also unexplained

The Russian dissident's body was discovered on March 12 at his home in southwest London by his daughter, Natalia Glushkova.

The court said yesterday that Aeroflot abandoned its claim against Mr Glushkov's estate just before proceedings were to begin in April.

The just said the airline realised its case 'was doomed to fail in its entirety'.

The Russian dissident's body was discovered on March 12 at his home in southwest London by his daughter, Natalia Glushkova (pictured)

Mrs Justice Rose added that Mr Glushkov was expecting to attent a hearing on March 12.

But Aeroflot sought an adjournment in the trial of its claim against him and a number of companies for alleged corruption.

Mr Glushkov was a senior director of the firm in the 1990s and Aeroflot was contesting payments to the other companies.

The court heard law firm Pinsent Masons wrote a 'shameful' letter asking 'hectoring and intrusive questions' of Ms Glushkova and her father's civil partner Denis Trushin.

Aeroflot dropped its claim one day after sending the letter on April 12.

Daniel Warents, for Mr Glushkov's estate, said his deceased client struggled to defend himself because he was in poor health - adding to the family's distress.

Mr Glushkov suffered from a blood disorder and high blood pressure.

Co-defendants of Mr Glushkov argued the the airline's withdrawal 'confirms their beleif that these proceedings were politically motivated'.

Aeroflot denied it conducted the case improperly.