Over-20s can register for a jab without an invitation.

The move came despite no official statement being issued by government through a press release or on its website or social media channels.

Government had earlier confirmed that anyone over 30 years or phase one priority groups should register for their vaccination through the online booking system or by calling 111 - even if they are yet to receive their letter.

Appointments will be issued either via email or phone as soon as vaccine supplies allow.

But it has emerged that under-30s can now also register without an invite.

Meanwhile, the Covid-19 vaccination programme will be prioritising jabs for people aged 16 and over who live with adults with weakened immune systems, following guidance from the UK’s Joint Committee on Vaccinations and Immunisations.

This includes conditions such as blood cancer, HIV and those on immunosuppressive treatment including chemotherapy.

Currently, people who have a weakened immune system and those on immunosuppressive treatment are receiving their vaccination through the priority four (clinically extremely vulnerable) or priority six (adults with underlying conditions making them susceptible to Covid) groups. However, the vaccinations haven’t been extended to those who live in the same household until now - unless they have been invited by age already.

The new guidance is based on evidence that susceptibility to infection is reduced in those who have been vaccinated.

Health Minister David Ashford said: ’I am asking anyone who fits this criteria to contact 111 and identify themselves as "living with", even if they haven’t received a letter yet, in order to arrange their vaccination.

’The team at 111 will then arrange two appointments to ensure they are prioritised in the booking schedule.’