Human trial of new COVID 19 vaccine starts in UK

"And understanding that it's not likely that things will get back to normal until there is a vaccine, so wanting to be part of that progress as well."

After this first phase, another trial is being planned for October, involving 6,000 people.

The Imperial team hopes the vaccine could be distributed in the UK and overseas from early 2021.

Meanwhile the Duke of Cambridge met volunteers taking part in Oxford University's trial, at the city's Churchill Hospital.

Prince William told the volunteers: "It's the most incredibly exciting and very welcome project that you're all doing which is why it's fascinating."

Many traditional vaccines are based on a weakened or modified form of virus, or parts of it, but the Imperial vaccine is based on a new approach, using synthetic strands of genetic code, called RNA, which mimic the virus.

Once injected into muscle, the RNA self-amplifies - generating copies of itself - and instructs the body's own cells to make copies of a spike protein found on the outside of the virus.

This should train the immune system to recognise and fight coronavirus without having to develop Covid-19.