Three members of the environmental movement Extinction Rebellion have vowed to continue their climate change fight after being convicted over their involvement in a protest which cost Amazon £24,000.

Bernard Kelly, 58, Alex Penson, 39, and Amy Pritchard, 37, were part of a group of climate protesters who blockaded the warehouse in Dartford on Black Friday last year, in an attempt to disrupt the company's busiest day of trading.

Extinction Rebellion said at the time its actions were aimed at drawing attention to the environmental impact of Black Friday and what it claims are destructive and wasteful business practices carried out by the giant online retailer.

The three protesters were arrested along with two others who refused to move from the depot at Littlebrook Business Centre on November 26 last year after being asked to by police who had been called to the site early that morning.

All three were charged with aggravated trespass and failing to leave the land.

They appeared before District Judge Peter Hayes at Medway Magistrates' Court on Friday, December 2.

Kelly, of Burntwood, Lane, London, Penson, of no fixed address but from the London area, and Pritchard, of Gainsford Road, London, had all previously denied the allegation, but when they appeared on Friday, they all changed their pleas to guilty.

The court heard more than 20 protesters blocked two entrances at the warehouse using bamboo, locks and banners with the words "Amazon Crime" and "Infinite Growth, Finite Planet" on them.

An access road outside the premises was obstructed shortly after 4.20am that day and campaigners locked themselves onto concrete and wooden structures.

When police arrived about an hour after being called, they found the groups were preventing lorries going in and out of the site via the two entrances.

In total, five people were charged with aggravated trespass, two others who were charged admitted their part in the protest at an earlier hearing and were given conditional discharges.

The five charged were protesting at one entrance, while other protesters at the other entrance gate were not charged in relation to the action as it is understood they moved off as the others were arrested.

On Friday, Judge Hayes heard the protesters had split into two groups after arriving at the site and that Kelly, Pritchard and Penson had been continually asked to move by police but had refused to do so.

Terry Knox, prosecuting, told Judge Hayes the protesters had sleeping bags, a mattress, umbrellas and even adults nappies and hot drinks which showed they had intended to stay at the site for a period of time.

Mr Knox added: "There was no violence at all, but at every stage they had been asked to leave and failed to do so.

"There was a cost to Amazon which was £24,000 as there was a delay to delivery services.

"A total of 15 lorries leave the site per hour and they were stuck, while others couldn't enter.

"Later at 2.48pm the police were stood down as that was the duration of the protest."

The court also heard both Kelly and Penson were of previous good character but Pritchard had relevant previous convictions and had been given fines and community orders, including unpaid work, for other protest actions she'd undertaken all over the country.

While in the dock, Pritchard, who is on Universal Credit and does a lot of community work in her area, told the judge: "Some people have to do things outside of the law because of the state of world.

"We have to connect with the reason why we are doing this and what's good for the community."

The judge also heard Kelly, who works in healthcare and earns about £50,000 a year, had never attended a protest before and had been nervous to go, but had done so because he gets scared about climate change and what it is doing to the planet.

Fighting back tears, he said: "My job is to protect my children and I don't know what else to do. Amazon's carbon dioxide emissions have increased by 40%. We are trashing our world."

Penson, a biologist who earns £33,000 a year, also said he was terrified by the rate of climate change.

He added: "We need to do something urgently as it affects all of us. We were keen to avoid disruption to the public that's why we targeted a company and Amazon is a huge employer and we want to help workers who are being exploited.

"Protesting is really important. We need to up the public pressure as the courts and police are making protests more difficult and [I] have no previous convictions, I want an absolute discharge."

Judge Hayes decided to place Pritchard on a six-month community order which will see her complete 80 hours of unpaid work.

She also has to pay a victim surcharge of £95.

Kelly was fined £1,000, and ordered to pay £500 costs and a victim surcharge of £190 and Penson was fined £600 and must pay £500 costs and a victim surcharge of £190.

All three vowed after the case to continue their climate change fight despite the penalties they received.

Pritchard said: "I'll absolutely be protesting again. At this stage what I know about the science and what we are accelerating into, I couldn't possibly stop.

"I am so, so concerned and full of grief for what we are doing to ourselves and I really, really hope there are some tipping points in social awareness and the activation of ordinary people to say 'no we don't want to die, we want to continue and we can live much better than this'."

All protesters had left the site by about 2.30pm on the day of the protest last year.

The Extinction Rebellion action coincided with a global day of action against Amazon in more than 20 countries by the Make Amazon Pay Coalition, which had issued a call to action asking workers and activists to participate in strikes, protests and actions.

At the time, a spokesman for Amazon said: "At Amazon, we take our responsibilities very seriously.

"That includes our commitment to be net zero carbon by 2040 – 10 years ahead of the Paris Agreement – providing excellent pay and benefits in a safe and modern work environment, and supporting the tens of thousands of British small businesses who sell on our store."

However, the company says it is aware there is "always more to do" and would continue to invest on behalf of its employees, customers, small businesses and communities in the UK."