When it comes to sick presidents, Proskovie Moshentsova has seen it all.

Andrew Harding talks to Dr Moshentsova

She's retired now, but 50 years ago, as a young doctor, she was summoned out of the blue to the Kremlin.

A KGB guard took her to a room and pointer towards a bed.

Dr Moshentsova never saw Stalin's face

"All I could see was a foot! It was sticking through a sort of curtain. I was told not to ask any questions. But to treat the toe which was infected."

It was only two years later that Proskovie found out that the foot belonged to Stalin.

Sworn to secrecy, she went on to treat a succession of elderly, ailing Soviet leaders - each one desperately struggling to cling on to life and to power.

Proskovie would spend weeks preparing Leonid Brezhnev for his rare public appearances.

Leonid Brezhnev "could barely walk or talk"

"He could barely walk or talk. But with the right medicines and encouragement, I could sort him out so he could make his speech or whatever. We all knew he was in no condition to run the country, but who was I to tell him," she said.

Decades later, and precious little seems to have changed.

Now it is Boris Yeltsin's turn to be wheeled out for the cameras, then whisked back into his luxury private hospital for another round of treatments.

Yeltsin: Is history repeating itself?

"He's a sick man. Just like Brezhnev. By the end he didn't know what was going on around him either. Yeltsin's entourage is to blame. They're just afraid of losing their jobs," said the doctor.

Nonsense, says Mr Yeltsin. But few people believe the official line any more.