OFFICIAL warning letters have been sent to those planning peaceful protests at King Charles III’s coronation saying new criminal offences to prevent disruption have been rushed into law.

Using tactics described by lawyers as “intimidatory”, the Home Office’s Police Powers Unit wrote to the campaign group Republic saying new laws could be used to stop “disruption at major sporting and cultural events”.

The new law, given royal assent on Tuesday, means protesters who block roads, airports and railways could potentially spend 12 months behind bars.

It also means anyone locking on to others, objects or buildings could face six months in prison and an unlimited fine.

Police will also be able to stop protesters by using stop and search powers if they suspect people are going to cause significant disruption.

The letter reads: “I would be grateful if you could publicise and forward this letter to your members who are likely to be affected by these legislative changes.”

It lists the creation of new criminal offences under the Government’s heavily criticised Public Order Bill.

The Home Office claims the timing of the laws is coincidental but lawyers have told Republic the letter could be seen as intimidatory.

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Graham Smith, the group’s chief executive, told the Guardian the letter was “very odd” and that Republic was seeking assurances from police that nothing had changed in relation to its plans to protest on coronation day.

He said: “We have been in direct contact with liaison officers and have met with senior commanders, who we have been very clear with about what we intend to do.

“Their response is that they are happy for us to proceed. But this letter has come out of the blue.

"Lawyers who have been in touch with agree it sounds like intimidation and we are currently waiting for assurances from police nothing has changed.”

Republic has been planning protests on Saturday under the banner “Not My King”, including one at the statue in Charing Cross of Charles I, who was beheaded in 1649.

Democracy campaigners had expected the new laws to be finalised on June 15 and were surprised that they had been brought forward.

Home Office sources told The Guardian that the new laws were not rushed through for the coronation but that they may be a “signalling point” to police and protesters.

Asked if the coronation was a factor, one source said: “I think it is, and Just Stop Oil has been pretty active in London recently.”

A statement from Home Secretary Suella Braverman said: “This legislation is the latest step the Government has taken against protesters who use highly disruptive tactics to deliberately delay members of the public, often preventing them from getting to work and hospital, as well as missing loved ones’ funerals.

“The range of new offences and penalties match the seriousness of the threat guerrilla tactics pose to our infrastructure, taxpayers’ money and police time.”

A Home Office source added that the letter sent to Republic was meant to inform rather than intimidate.