“This is dangerous for you and for me. There’s a real climate of fear”, says the doctor as he sits nervously in a room off intensive care at the JM de Los Rios Children’s Hospital in Caracas.

Dr Huniades Urbina is trying to expose the desperate shortage of drugs and medical supplies in what should be the best equipped paediatric unit in Venezuela, but he is taking a great risk. The corridors are patrolled by militia loyal to the governing party of the socialist revolution once led by Hugo Chavez and now led by his successor, Nicolas Maduro, the current president.

Officially they exist to help and reassure patients in a city rife with violent crime but many doctors find them intimidating, says Dr Urbina, who until recently was the hospital's director of intensive care.

“I was supposed to retire in five years time and two years ago they fired me (from the directorship) because I always fight for human rights. In this kind of government every time you say the truth they tell you are breaking the law. But I’m an old man now so I’ve got nothing to lose.”

Quality health care for everyone in Venezuela was one of the great promises of the revolution, but today the government is unable to provide it for anyone, no matter how wealthy they are. The increasingly desperate economic crisis has seen the government run short of foreign currency with which to import medical supplies. Huge numbers of medicines are now hard or impossible to find, from antibiotics and painkillers to anti-epilepsy and chemotherapy drugs.