Coronavirus patients on NHS wards have started receiving a controversial anti-malarial drug - despite debate over its effectiveness.

Hydroxychloroquine is being used at Barts in London and the Royal Devon and Exeter to keep critically ill coronavirus patients alive.

President Trump described the drug as a 'game changer' and it has been added to the Chinese guidance for tackling the disease, but up until now the NHS has strongly discouraged its use.

Hydroxychloroquine is being used at Barts in London and the Royal Devon and Exeter to keep critically ill coronavirus patients alive

Trump's backing of the drug has caused rows in the US and in France one cardiologist said the drug damaged the hearts of 54 coronavirus patients, four of whom died.

Hydroxychloroquine is a synthetic compound that was created 75 years ago as a malaria treatment. It is also used to treat chronic inflammatory illnesses such as lupus and rheumatoid arthritis.

It is thought that Chinese doctors started using it after it showed promising results on animals with Sars and Mers.

Chinese medical authorities have recommended its use but have not released supporting data to back up its effectiveness.

WhatsApp messages, seen by The Telegraph, from doctors involved in administering the drug at Barts imply that the drug will be given to patients for five days at a time.

They also reveal fears about its long-term availability.

According to the Sunday Telegraph, Barts Health NHS Trust (pictured) has also been using the rheumatoid arthritis drug tocilizumab for some severe coronavirus cases

One message said that evidence is limited but people are being recruited for trials - meaning little impact in the short term but potential trouble over the next two or three months if other trusts or countries adopt the same approach.

India announced a ban on the export of the drug earlier this month but reversed its decision after pressure from the US.

Donald Trump has been criticised for endorsing the drug despite a lack of evidence of its effectiveness. 'What have you got to lose? Take it,' he said last weekend.

A trial of the drug began in the US on Thursday, overseen by the National Institutes of Health.

According to the Sunday Telegraph, Barts Health NHS Trust has also been using the rheumatoid arthritis drug tocilizumab for some severe coronavirus cases.

Donald Trump has been criticised for endorsing the drug despite a lack of evidence of its effectiveness. 'What have you got to lose? Take it,' he said last weekend

A spokesman for Barts said: 'Barts Health NHS Trust has convened an expert clinical group to consider novel medications in the treatment of Covid-19.

'The evidence base is limited for all such drugs and we are actively recruiting patients to major clinical trials that have been prioritised by the Dept of Health and Social Care.

'These include hydroxychloroquine, kaletra, steroids and remdesivir.'

He added: 'For a small number of carefully selected patients, we have recommended some novel therapies for immediate use, including immunomodulatory drugs such as tocilizumab.'

A spokesman for the Royal Devon and Exeter NHS Foundation Trust said patients would be selected at random by computer for participation in the hydroxychloroquine trial.