The eight-part series, to be screened later this year, continues to chart the lives and loves of the Crawley family and their retinue of servants but this time against the backdrop of the First World War.

The bloody military conflict will lead to personal tragedy for both masters and servants alike and will mean life in the great house will never be the same again.

It will also lead to the arrival of several dashing and eligible young officers who will break hearts and further complicate the tangled love lives of the three Crawley sisters.

Our pictures will ease the concerns of fans who had feared the advent of war would move the drama away from Downton Abbey and on to the battlefields of Europe.

In fact, some sources close to the production say the new series will draw on events that actually took place at Highclere Castle, which became a military hospital between 1914 and 1916.

The idea of turning Highclere into a hospital was the brainchild of Almina, fifth Countess of Carnarvon, a leading light of the Edwardian social scene who was keen to do her bit for the war effort.

A source said: ‘It wouldn’t be right to say Downton becomes a military hospital but there are similarities between what happened at Highclere at what happens at Downton.’

The introduction of several new characters above and below stairs will only exacerbate existing tensions in the house.

The growing friendship between Bates, the Earl of Grantham’s disabled valet, and Anna, the housemaid, is about to be shattered by the arrival of the ex-soldier’s scheming wife Vera Bates, played by the Irish actress Marie Doyle Kennedy.

This will be her first introduction to the show’s army of fans. Other new characters include Spooks star Iain Glen as Sir Richard Carlisle, a wealthy media magnate, Cal Macaninch, the star of Wild At Heart and Holby Blue, as a new valet called Lang, Zoe Boyle as Miss Lavina Swire, and Amy Nuttall as a flirtatious parlour maid called Ethel.

The new series of Downton is scheduled for September and will be followed by a Christmas special.