The group and their supporters chanted “We are unstoppable, another world is possible”, as they were led to the cells through the dock by security officers.

Raj Chada, a solicitor at Hodge Jones and Allen, a law firm that supported the protesters, said: “With these prison terms, the long and honourable tradition of civil disobedience is under attack again.

“Rather than leaving courts to imprison those that raise the alarm, it should be the Government that acts to protect us against the climate crisis.”

Heralding the sentencing, Priti Patel, the Home Secretary, said: “We will not stand by while these reckless and selfish criminals disrupt the freedoms and livelihoods of hard-working people.”

The Government plans to introduce new measures to clamp down on protests, including allowing police to stop and search people where there is a reasonable suspicion they are carrying items intended to cause disturbance, such as glue.

Statement from Insulate Britain

A statement from the nine activists jailed was read by an Insulate Britain supporter outside the Royal Courts of Justice after the ruling.

It read: “Over the last nine weeks, 174 ordinary people have held the Government to account, asking that they deliver on their most basic of duties, to protect the British people, the economy and all we hold dear in our society.

“Your Government has now chosen to act. It has chosen to imprison us for this demand.

“By imprisoning us, the Government shows its cowardice. They would rather lock up pensioners than insulate their homes.

“They would rather lock up teachers than create thousands of proper jobs.

“They would rather lock up young people than take practical steps to reduce emissions.

“They will lock us up and leave thousands to die of cold this winter. We knew we would face prison when we took this action, but we could not stand by while the Government betrays the general public.”

Insulate Britain vow to block roads again at earliest opportunity 

Ben Taylor told the court on Tuesday if he was not in prison he would “go and block the motorway at the earliest opportunity and will continue to do so until the Government makes a meaningful statement and acts on it”.

He added: “If you somehow manage to stop all non-violent protests, then things will only turn violent.”

Smart told the court she was there to “ensure future survival”.

She said: “I am doing everything I can to protect the most vulnerable people in society. We are all vulnerable in a climate crisis. No one is immune and no one is safe.”

She compared watching the climate crisis to seeing a child trapped in a burning house, and added: “I cannot stand by and watch. I would run to them.”