Protesters vowed a “sustained campaign of direct action” to stop new roads being built as regional transport chiefs agreed the blueprint for travel over the next two decades.

A handful of Extinction Rebellion campaigners unfurled banners and shouted from the sparse public gallery at Bristol City Hall as the West of England Combined Authority (Weca) committee adopted the Joint Local Transport Plan (JLTP4).

Weca was criticised by a succession of public speakers for failing to take the climate emergency it declared last year into account in the document.

Although the plan sees walking, cycling, rail and buses becoming the “natural” way to travel around Bristol, South Gloucestershire, North Somerset and B&NES under a mass transit system, road-building and widening is a major part of the £8.9billion wish-list of projects for completion by 2036.

They include new bypasses, link roads and motorway junctions on the M4 and M5.

James Mee, from Extinction Rebellion, told the meeting on Friday (March 20): “The road-building plans in the JLTP4 are very concerning.

“More road capacity will exacerbate climate impacts, damage communities and destroy the countryside.

“Extinction Rebellion demands that you cease building any more roads that increase overall capacity.

“If you fail to meet this demand, you will face a sustained campaign.

“Our campaign will not be limited to seeking a judicial review.

“We are prepared to take non-violent and peaceful direct action to stop these roads being built.”

South Gloucestershire Council cabinet member for transport Cllr Steve Reade said: “It is important the plan is approved so we can progress with delivery of our ambitions of greater transport choices so our residents can travel more sustainably.

“To meet our target of zero-carbon by 2030 we will need to go further faster, so there is a need to work up evidence to determine what carbon neutrality looks like in transport terms for the region.

“With this information we can update and review the plan.

“We need to start now in responding to the climate emergency and this JLTP provides a mandate for that.”

Weca overview & scrutiny committee chairman and Bristol city Green Cllr Stephen Clarke said afterwards: “I have real concerns about the plan.

“There have been claims that the plan could be quickly reviewed, however in reality this process would take at least a couple of years.

“In the meantime Weca and its authorities have all declared climate emergencies and the plan needs to do much more to reflect this.”