The Labour leader, a lifelong republican, took part in the Buckingham Palace ceremony to become a member of the ceremonial body, which enables him to receive confidential security briefings.
Labour said Corbyn complied with the usual processes, which tend to involve kneeling on a stool before kissing the Queen’s hand.
But it is understood Buckingham Palace does not force privy council members to do things they are not comfortable with and that Corbyn did not kneel.
Speaking to ITV News before the ceremony, Corbyn signalled he would not be kneeling. “I don’t expect to be kneeling at all, no,” he said. “I expect to be nominated to the privy council and that’s it.”
Corbyn had initially indicated he would have to think about whether to take part in the ceremony, saying there were “some things that ought to change in our society and maybe that’s one of them”.
Last month he turned down the chance to be made a member of the privy council in person by the Queen, with his office saying that private engagements made such a ceremony impossible.
There was speculation that he might try to become a member by an order in council, rather than attending in person, but he travelled to the palace on Wednesday to take part in the initiation rite at 5.30pm.
It is possible, and indeed frequent, for members of the privy council to be appointed without meeting the monarch through a device known as an order in council, but would have been unusual for a party leader to use such a course.
The Royal Encyclopaedia describes what the protocol involves: “The new privy counsellor or minister will extend his or her right hand, palm upwards, and, taking the Queen’s hand lightly, will kiss it with no more than a touch of the lips.”
The late former cabinet minister and republican Tony Benn said in his diaries that he kissed his own thumb instead of the Queen’s hand.
As well as that, new members are meant to swear to defend the monarch against “all foreign princes, persons, prelates, states or potentates”.
As a member of the council, which is the oldest functioning legislative assembly in the UK, Corbyn now has the right to use right honourable as a title.
The council is made up of 600 senior figures including politicians, which tends not to transact any serious business. Not many of its members turn up to meetings, which happen roughly once a month.
Michael Foot and Neil Kinnock both became privy counsellors, which entitled them to security information and briefings they might otherwise have not been able to obtain.
While MPs have to swear or affirm allegiance to the Queen, the oath required of privy council members is more extensive.
The current wording, which has been around since Tudor times, states: “You will not know or understand of any manner of thing to be attempted, done or spoken against Her Majesty’s person, honour, crown or dignity royal, but you will let and withstand the same to the uttermost of your power, and either cause it to be revealed to Her Majesty herself, or to such of her privy council as shall advertise Her Majesty of the same.
“You will in all things to be moved, treated and debated in council, faithfully and truly declare your mind and opinion, according to your heart and conscience; and will keep secret all matters committed and revealed unto you, or that shall be treated of secretly in council.”
Since becoming Labour leader, Corbyn has come under intense criticism from some sections of the media over his participation in ceremonial events.
His critics have variously attacked him for not bowing low enough at the Cenotaph on Remembrance Sunday, appearing not to sing the national anthem at a service and “snubbing” the Rugby World Cup opening ceremony by turning down an invitation to attend.
Corbyn observed the two-minute silence for Armistice Day with children at a pre-school in Crawley, West Sussex, holding hands in a circle. He also sang the nursery rhyme Incy-Wincy Spider with them.
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