Police will give a “firm” but “fair” response to “extremely frustrating” plans for further protests by Extinction Rebellion, the Metropolitan Police Commissioner has said.

The environmental protest group has posted online about a forthcoming climate demonstration, which is due to last for two weeks from August 23, similar to its previous protests in central London in September 2019.

Dame Cressida Dick said she is “very disappointed” about the plans.

She told LBC Radio on Thursday: “Many people may be very interested in the cause; I don’t think London supports hugely disruptive protests which cause people not to be able to go around their normal business at all.

“And the fact that they’ve chosen to do it over the August bank holiday, which for us is always our peak weekend of the year, is extremely frustrating, frankly.”

Dame Cressida said police previously took pre-emptive action over the group’s last protest activity, including removing “a huge amount of materials” from a warehouse which were likely to be used “to form constructions that would be very difficult to take down” and stopping people putting manure on a road and causing damage.

“Whoever turns up next time, they will be met with a fair, lawful – and we have to stick within the law – but firm, and where we possibly can be, pre-emptive response,” she added.

“They’ve indicated they’re interested in the City of London. I want to reassure you that we work incredibly closely with our colleagues in City of London Police and it will be a joint operation and we will seek to balance people’s rights.

“People have the right to assemble, they have the right to express themselves, they have the right to cause a reasonable amount of disruption.”

The Commissioner claimed that Extinction Rebellion have been “disingenuous” in the past and “they certainly don’t seem in control of their colleagues”.

She added: “Often what they say turns out not to be true. On this occasion, as far as I’m aware, they have not spoken to us directly at all, despite many, many attempts by us. So I would ask them to speak to us.”

In a statement on its website, Extinction Rebellion said it will “not be pre-liaising actions” with police for any of the London-based actions that will be part of its “Impossible Rebellion” this month “unless insisted upon by the action team”.

Referring to a recent UN report calling for radical change with regard to climate policy, a spokesman said: “On August 23, Extinction Rebellion will be back out on the streets to demand that change – and, in the first instance, an immediate halt to all new fossil fuel investment.”

Dame Cressida’s comments came after four more Extinction Rebellion activists had their convictions overturned at the Old Bailey on Wednesday.

Campaigners have recently won a slew of victories after the Crown Prosecution Service (CPS) dropped the cases.

The environmental group says 2,500 people have been prosecuted since April 2019 and that “potentially hundreds if not thousands of the resulting convictions could be unsafe”.

The Supreme Court overturned the convictions of four demonstrators at an arms fair in June after it found they had “lawful excuse” for the offence.