Lord Grantham receives a letter to inform him that King George and Queen Mary will visit Downton Abbey for one night on their journey through the English Midlands. This reaffirms the life of privilege enjoyed by the Granthams and the English aristocracy for centuries. For that reason, it is the best of times.

Most, but not all, of the family rejoice in the king's visit. Tom, a professed Irish republican and Grantham's son-in-law, poses a potential risk to the smooth running of the event.

But it is the worst of times because the English aristocracy is being challenged by the looming republican push in Ireland, and a feeling among the working class that the era of privileged entitlement must change.

On a practical side, the expense of operating a vast estate like Downton Abbey is a constant challenge. As one of the household staff observes, Downton Abbey and the Crawley family are the heart of the region and to sell it and move away would be destructive to the local community.

The shift in attitude and cultural norms is symbolised simply in the Roaring Twenties bob haircut worn by Lady Mary Crawley. Change is coming and the barriers of class divisions are weakening.

Maggie Smith as the Dowager Countess of Crawley is a delight. If words were swords, hers would slice through steel. Her barbs are confidently counteracted by Baroness Merton.

The visit provides a self-contained story to reinvigorate Downtown Abbey without the need for a continuing saga such as the one that unfolded during the television series.

Conspiracies, revolutionary plots, the presence of a mysterious colonel, deep family secrets and class distinctions, including a struggle between the king's "Page of the Rear Stairways" and Downton's house staff, present an entertaining diversion.

Those of you who viewed the televisions series will know the multitude of plot strands that exist both upstairs in the lives of the rich and privileged, and downstairs among the common working folk, who take pride in their roles as the unseen foundation of the English aristocracy.

All your favourites are here, from Lord and Lady Crawley to Daisy, Barrow, Mrs Hughes and Carson from the downstairs coterie.

It is understood that nothing untoward will occur.

Downton Abbey is the movie equivalent of sipping tea and savouring cucumber sandwiches and cream cakes. It is all pleasant and sweet.