Britain on Friday claimed its streamlined approach to developing Covid vaccines and support for biotech firms helped it to steal a march on other countries still struggling to implement a roll-out.

The former head of the UK vaccines taskforce, Kate Bingham, who left the role at the end of December, said the country's size and lack of red tape made it more attractive to vaccine developers.

The comments come as the European Union pushes drugs firm AstraZeneca over supplies of the jab it developed with Oxford University, which have been delayed because of production issues.

Brussels has insisted it must keep its commitments, diverting deliveries from Britain if necessary, and potentially creating a post-Brexit stand-off between London and Brussels.

Britain has so far given the green light to three vaccines -- Pfizer/BioNTech, AstraZeneca/Oxford and Moderna -- and has already vaccinated some eight million people.

UK regulators are now set to review a fourth jab from US biotech firm Novavax, after it announced on Thursday successful clinical trials in Britain.

The government has ordered 60 million doses of the jab, which will be produced in northeast England.

Franco-Austrian firm Valneva on Thursday began large-scale production of its own vaccine for clinical trials from its factory in Scotland.

Bingham said the UK had been able to get ahead by acting swiftly to create a database of about 400,000 volunteers for quick and high-quality vaccine trials early last year.

"We're clearly at a disadvantage in terms of size and buying power so the way we sought to address that was to be nimble and as cooperative and supportive as we possibly could be," Bingham told BBC radio.

"That was the UK offer, as it were, so that's how we were able to persuade Novavax to come and do their trials in the UK and therefore secure vaccines for the UK should that vaccine be safe and effective."

The brisk pace contrasts with the EU, which Britain left after decades of membership last year. The bloc has struggled to get hold of as many doses and administer them.

Bingham, who left a leading international life sciences venture capital firm to head the UK Vaccine Taskforce, said the issue must be resolved by politicians.

But she noted Britain had started scaling up the manufacturing of the AstraZeneca jab over the last year.

"It's that early work that was done by the industry voluntarily, not based on contracts or requirements but a voluntary coalition of the different companies, that is what's ultimately made the difference as to why we're so far ahead on manufacturing," she added.