The Duke of Sussex has taken his place among minor, non-working members of the Royal family at the Coronation service, where he was relegated to the third row.

The Duke was seated at Westminster Abbey alongside his cousins, Princesses Beatrice and Eugenie.

He was placed between Eugenie’s husband Jack Brooksbank and Princess Alexandra, Queen Elizabeth II’s 86-year-old cousin.

He appeared relaxed as he arrived at the Abbey flanked by his cousins.

He walked down the nave alone, nodding and smiling to several members of the congregation, mouthing “hello” to someone he recognised.

The Duke’s view appeared to be somewhat blocked by the large red feather worn by his aunt, the Princess Royal, seated directly in front of him.

Onlookers joked on social media that she had worn the “view obscuring” feather on purpose.

In reality, it is the plume of the Blues and Royals, whose uniform she is wearing.

The Duke arrived in the UK on Friday, just hours ahead of the ceremony.

However, it will be a fleeting 24-hour visit as he dashes back in a bid to see his son, Prince Archie, on his fourth birthday, which is today.

As a non-working royal, he will not take part in the procession back to Buckingham Palace nor appear on the balcony.

It is thought unlikely that he will return to the palace for a private family lunch or even appear in the official portraits, to be taken afterwards.

A source close to the Duke said he would “do his best” to attend as many events on the day as possible.

But he has not made any firm commitments as it will depend on how the timings fall later on.

As The Telegraph first revealed, the Duke - who served for 10 years in the Army and did two tours in Afghanistan - has not been permitted to wear military uniform because he is not a working member of the Royal family.

Instead, he is in a morning suit.

The decision follows royal protocol set at previous state occasions, including the late Queen’s funeral last September.

Buckingham Palace said all members of the Royal family were wearing morning dress with mantles appropriate to the most senior order of which they are members - Garter, Thistle or Royal Victorian Order (RVO).

The Duke is a Knight Commander of the RVO, a rank that does not have a robe.

Prince Harry made no specific requests concerning his outfit for the Coronation but was willing to wear whatever was asked of him, sources confirmed.

The Duke's brother, the Prince of Wales, is wearing the Ceremonial dress uniform of the Welsh Guards.

At the late Queen’s coronation in 1953, peers were required to wear lavish, floor-length coronation robes.

For the King's service, hereditary peers were initially told to dress down in keeping with the pared back tone of the ceremony before a last-minute U-turn indicated that they could wear the robes should they wish.

In order to take part in the portrait session, which will take place after the flypast, the Duke would be required to wait in the background for some time.

It is debatable whether he would want to join the family for an informal lunch, likely to take place before the portrait session begins.

Hugo Burnand, the official Coronation photographer, will not know until the moment whether he will have the unenviable task of neutralising family tensions and ensuring everyone poses with a suitably big smile.

Lord Soames, a close friend of the King, this week disclosed that the Duke’s behaviour towards his family had come as a "terrible blow" to the monarch and a “most tragic” turn of events.

The Duke confirmed in mid April that he would attend the Coronation amid growing hopes of a reconciliation with his father.

The Duchess of Sussex opted instead to remain in California with their children Prince Archie and one-year-old Princess Lilibet, in order to host the young Prince’s birthday party.

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