Around 3,000 people will take part, with half receiving a dose of Moderna's current booster and the rest the biotech company's new jab containing genetic material for the Omicron variant.

The clinical trial, led by a team at St George's Hospital in London, will start later this week. Up to 29 hospitals in England, Scotland and Wales are expected to take part.

'Protecting the country for years to come'

Health and Social Care Secretary Sajid Javid said: "The UK is a world leader when it comes to the research and development of vaccines and medicines, bolstered by our renowned life-sciences industry.

"I want this country to be the best place in the world to launch clinical trials.

"I urge anyone eligible to take part in this vital research and play their part in protecting the country for years to come as we learn to live with COVID-19."

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The collaboration with the National Institute for Health Research (NIHR) is a sign of closer ties between the UK and Moderna.

The health secretary last week met the company's boss Stéphane Bancel in Boston. There has been speculation that Moderna is planning a significant investment in a UK research and manufacturing hub.

Mr Bancel said: "The UK and NIHR have been pioneering in their work to study vaccines and therapeutics throughout the global pandemic and have built up world class clinical research capabilities.

"We look forward to continuing our work with the NIHR and engaging further with the life-sciences community in the UK."

Combined Autumn booster for Omicron and Delta variants

Moderna has already started a trial of the Omicron vaccine in the US. Pfizer is also about to start a clinical trial of its own vaccine targeted at the highly infectious variant.

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The chief medical officer of Moderna recently told Sky News that it was likely an autumn booster would combine protection against both the Delta and Omicron variants.

Volunteers in the new trial must have been COVID-free since the beginning of November 2021, and had their last vaccine dose at least three months prior to joining the study, which is recruiting for the next four weeks.

The study will evaluate the immune response and safety of the variant jab.