It will be just the third time that the Queen has not attended the event, having last missed it in 1963 when she was pregnant with Prince Edward.
The decision was taken yesterday, as the Queen has continued to suffer episodic issues since last autumn.
A statement from Buckingham Palace said last night: “The Queen continues to experience occasional mobility problems, and
in consultation with her doctors has reluctantly decided that she will not attend the State Opening of Parliament tomorrow.
“At Her Majesty’s request, and with the agreement of the relevant authorities, the Prince of Wales will read the Queen’s Speech on Her Majesty’s behalf, with the Duke of Cambridge also in attendance.”
According to Number 10 last night: “The Prime Minister fully respects the wishes of Her Majesty and is grateful to the Prince of Wales for agreeing to deliver the speech on her behalf.”
The speech will lay out the Government’s legislative plans for the next sitting of Parliament, and is expected to include details on new laws designed to tackle “disruptive” protests.
The Public Order Bill will include new offences relating to certain protesting tactics, and follows on from the disruption caused by groups such as Extinction Rebellion, Insulate Britain and Just Stop Oil in recent months.
It is one of 38 Bills due to be included today.
The speech is expected to lay out new criminal offences of ‘locking on’ and going equipped to ‘lock on’ to other people, objects, or buildings in order to cause serious disruption. This will carry a maximum penalty of six months’ imprisonment, an unlimited fine, or both, and an unlimited fine, respectively.
Interfering with ‘key national infrastructure’ such as airports, railways, or printing presses will also be outlawed, which could carry a maximum 12 months in prison, an unlimited fine, or both.
Obstructing transport works such as HS2 will also be made illegal, and punishable by up to six months in prison or an unlimited fine, or both.
Commenting on the new measures the Home Secretary Priti Patel said: “The law-abiding, responsible majority have had enough of anti-social, disruptive protests carried out by a self-indulgent minority who seem to revel in causing mayhem and misery for the rest of us.
“The Public Order Bill will give the police the powers they need to clamp down on this outrageous behaviour and ensure the British public can go about their lives without disruption.”
The Government is also expected to use the speech to bring forward changes to Northern Ireland’s post-Brexit trading arrangements.
Reports of proposed changes come as the Government grapples with the implications of Sinn Fein’s success in the Stormont Assembly elections.
However, Deputy Prime Minister Dominic Raab refused on Sunday to say whether new measures would be included.
“What we’re going to be focusing on this week is what our plans are to drive up the economy, protect the cost of living,” Mr Raab told Sky News.
Speaking ahead of today’s events, Prime Minister Boris Johnson said: “This Queen’s Speech will get our country back on track, and I will strive – and this Government will strive – night and day to deliver it.
“Because in spite of everything we have been through, we are going to ensure that over the two years we have left in this parliament, we spend every second uniting and levelling up this country, exactly as we said we would.”