Volunteers who took part in Covid vaccine trials will be offered two more jabs - taking their total up to four - so they can get the right paperwork to travel, health chiefs have said.

       The extraordinary government announcement means around 20,000 people will be eligible for four jabs in total, despite a lack of safety data on the issue.

       Health officials said they had been forced to make the arrangement because many foreign countries will not accept people who had the Novavax and Valneva jabs, which are not yet licensed.

       Individuals who took part in the trials will be offered one-to-one counselling about whether they want to go ahead with two more jabs, which would be Pfizer.

       For months, all those who took part in trials of Novavax and Valneva have been unable to travel to countries in Europe and beyond to see family, work or go on holiday.

       But since their trial vaccines were unlicensed, they cannot prove their vaccination status outside the UK, which means that many countries require them to quarantine.

       Until now, because they had already had two doses, they were also not allowed other vaccines through the NHS.

       Earlier this year The Telegraph revealed that Britain's vaccines tsar, Dame Kate Bingham, was among those prevented from travelling abroad because she took part in early vaccine trials.

       If the vaccines are licensed, those who had them as part of a trial would be able to travel abroad, without having extra jabs.