Duke and Duchess of Cambridge may miss Queen's festive dinner

The Duke and Duchess of Cambridge may not be included in the Queen’s “Christmas bubble” as their three young children will be considered a risk to their elderly great-grandparents, The Telegraph understands.

The Queen, 94, and Duke of Edinburgh, 99, will be limited to spending the festive period with two other households, just like the rest of the nation, meaning that the traditional mass gathering at Sandringham is off the table.

A final decision about who will join Her Majesty is not expected to be made for another few days but royal sources have acknowledged that factors such as the monarch’s age and relative frailty will be taken into account.

The elderly couple are in the most at-risk bracket for coronavirus and have thus far been carefully shielded by what has become known as “HMS bubble,” comprising a vastly reduced staff.

Buckingham Palace doctors will advise the Queen about the most sensible way forward and will be particularly mindful of the Duke’s frailty after he was hospitalised just before Christmas last year with a pre-existing condition.

Watch: Which royals will be in the Queen's Christmas bubble?

After taking advice, the decision will be made in consultation with all members of the family, many of whom are likely to want to see other relatives.

“They will sort it out between them, it will be about what’s practical,” a source said, adding that the potential risks surrounding young children who have been mixing with others at school would “clearly” be taken in account.

Prime Minister Boris Johnson has warned families they must make a "personal judgment" about the risks of coronavirus to vulnerable loved ones.

Although three households can mix from December 23 to 27, the bubble has to remain exclusive, meaning that families cannot shift from one group to another.

The Cambridges are likely to want to take the opportunity to spend Christmas with the Duchess’s parents, Carole and Michael Middleton, either in Bucklebury, Berkshire, or at their own home, Anmer Hall, in Norfolk, having spent Christmas at Sandringham for the last three consecutive years.

The Duchess of Cornwall might similarly want to bubble up with her own two children and five grandchildren.

Newlyweds Princess Beatrice and Edoardo Mapelli Mozzi are likely to join forces with heavily pregnant Princess Eugenie and her husband Jack Brooksbank and their parents, the Duke and Duchess of York, who are divorced but still live together at Royal Lodge, Windsor.

Prince Edward and the Countess of Wessex, and their two children Lady Louise Windsor, 17, and James, Viscount Severn, 12, are considered a more likely option to join the Queen as the older children will be better able to adhere to social distancing guidelines. The monarch is particularly close to the Countess.

Another decision the couple will have to make is whether to remain at Windsor Castle, where they spent the most recent lockdown together, or to move to Sandringham.

If they decide to decamp to Sandringham, the small royal party is not expected to make the traditional walk to St Mary Magdalene Church for the Christmas Day service in order to avoid the prospect of crowds gathering.

However, one idea said to be under consideration if they do opt for Sandringham is to invite wider family members to a traditional Boxing Day shoot, which, due to its classification as an organised outdoor sport, would allow up to 30 royals to attend.

If they remain in Windsor, it will be the first time that the Queen has spent Christmas there in 37 years.

The Duke and Duchess of Sussex will remain in the US.

Watch: Who is The Queen?