A retired hospital medical director has become the latest doctor to die from coronavirus in the UK.

Dr Alfa Saadu, 68, was volunteering at the Queen’s Victoria memorial hospital, in Welwyn, Hertfordshire – one of the counties worst hit by the virus – when he became ill. His son Dani confirmed that his father had died after a two-week battle with the disease.

Dr Saadu had not specifically answered the call for retired doctors to return to the front line to tackle the pandemic. But his death will raise more questions about the wisdom of the government’s drive to encourage former medics back to work when older people are more at risk from coronavirus.

Dr Saadu had retired from the Princess Alexandra Hospital in Harlow in 2016 after a distinguished 40-year medical career, but was helping out behind the scenes at his local hospital in Welwyn.

It was announced on Sunday that Amged el-Hawrani, a 55-year-old ear, nose and throat consultant from Burton hospital in Derbyshire, had died. A 63-year-old surgeon, Adil el Tayar, also died last week after volunteering in A&E departments in the Midlands to help the NHS cope with the pandemic. GP Dr Habib Zaidi, 76, also died last week after showing “textbook symptoms” of the virus.

Dani said his father was “a very passionate man, who cared about saving people. “As soon as you spoke to him about medicine his face would light up,” he said. “My dad was a living legend, worked for the NHS for nearly 40 years saving people’s lives here and in Africa. Up until he got sick, he was still working part-time saving people.”

He added: “He was a massive family man and we did everything together. Family came first. He left two sons and a wife, who is a retired doctor herself in occupational health.”

Lance McCarthy, chief executive of Princess Alexandra Hospital, said Dr Saadu would be “remembered fondly by many”. He added: “Alfa was well-known at the trust for his passion for ensuring our patients received high quality care.”

The former health secretary Jeremy Hunt was among the many who paid tribute to Dr Saadu’s heroism.

This is so tragic. These are true heroes, they could have stayed at home and protected themselves but put themselves back into the fray to save lives. When this is over, we must never forget people like Alfa Saadu https://t.co/t6Rcloay3E — Jeremy Hunt (@Jeremy_Hunt) April 1, 2020

Abbas Mirza, a former colleague, said Dr Saadu’s death underlined the continued sacrifice NHS workers were making to save lives.