Millions of adults in the UK are set to be offered the Covid booster vaccine with government advisors considering extending the jab to all adults under emergency measures to limit the spread of the Omicron variant.

A decision from the Joint Committee on Vaccination and Immunisation (JCVI) on expanding the programme and cutting the gap before a third dose could come as early as Monday, November 29.

The Scottish Government announced that six cases of the Omicron variant have been identified in Scotland.

These follow a third which was detected in England on Sunday. The person had travel links to southern Africa and visited Westminster before leaving the county.

It was thought the individual visited the wider borough and not Parliament.

Close contacts of positive Omicron cases are being ordered to isolate for 10 days even if they have been vaccinated under emergency measures that were announced over the weekend.

Britain will have an urgent meeting of G7 health ministers on Monday to discuss the Omicron variant.

The first two infections were identified in Nottingham and Essex, where officials were ordering PCR tests for customers of a KFC in Brentwood as far back as November 19.

Dr Jenny Harries, the chief executive of the UK Health Security Agency, acknowledged it was “very likely” that further cases of Omicron would be discovered in the coming days.

But Health Secretary Sajid Javid told families they should plan for a “great” Christmas “as normal” and insisted it was “nowhere near” time to reintroduce social distancing rules and work-from-home guidance.

It was hoped the new measures would buy time for scientists to gain a greater understanding of Omicron as ministers put the NHS on notice to deliver many more vaccines every day.

JCVI deputy chairman Professor Anthony Harnden said extending the age range for boosters and reducing the gap between second and third doses was “a sensible strategy”.

He told BBC Radio 4’s Broadcasting House that adults aged 18 to 39 should expect third jabs to be offered to them “earlier than we had previously envisaged”.

The group was also considering whether second doses should be offered to 12- to 15-year-olds.

Whitehall sources were hopeful the decision may come on Monday, but could not rule out Tuesday for the JCVI’s announcement.