The RSPB has staged a “once in a generation” protest against plans for the a nuclear power plant to be built on a nature reserve in Suffolk, which they claim will endanger more than 6,000 species.

All Creatures Great and Small actor Samuel West joined volunteers and representatives from the charity outside the Department for Business in Westminster on Thursday as they lobbied Business Secretary Kwasi Kwarteng to drop proposals for EDF’s new Sizewell C nuclear power plant on the Minsmere reserve.

The proposals would see a breeding area the size of eight football pitches lost, as well as some three million fish, according to RSPB estimates.

West and other volunteers read out hundreds of names of species which they say would be put at risk by the power plant outside the department while holding up banners which said: “Do the right thing for nature Kwasi #loveminsmere”.

The actor, who plays vet Siegfreid Farnon in Channel 5’s James Herriot adaptation, said of Minsmere: “I don’t think I know anywhere lovelier. It’s an extraordinary collection of habitats, internationally important numbers of threatened species, and we’re very lucky to have it.

“So if we can’t protect this, then we can’t protect anything.”

He added: “I hope Siegfried would be here shouting along with me. I think that what he does, as a matter of course, is try to protect innocent creatures from suffering. So I think the right place for people who have that in the heart of that being would be on that line behind that banner.”

RSPB Minsmere is a nature reserve on the Suffolk coast, and is home to more than 6,300 species of wildlife. The reserve saw the return of avocets to the UK after they were extinct in the late 1990s, when a pair nested on the site of the reserve which was then acquired by RSPB. The avocet is now the logo for the charity.

More than 100,000 people have signed a petition in support of Minsmere.

Jeff Knott, operations director for Central & Eastern England at RSPB, said: “We haven’t done this for a generation.”

He added: “This is quite unusual for RSPB to do something like this. We’re not naturally an organisation that comes and stands and paints avocets on the pavement and holds banners up in front of Government departments.

“But Minsmere has every protection under the sun, and if Minsmere can be put at risk, nowhere is safe and sooner or later a line in the sand has to be drawn. This is our line in the sand.”

The charity insists it remains neutral on the question of nuclear power, but of plans for the EDF plant to be built on Minsmere land, Mr Knott said: “We’re facing a nature and climate emergency. We’ve lost 50 million birds in the last 40 years, and we need to find solutions that work for both bits of that emergency.

“We cannot afford to keep trading off one against the other. So we’re here today saying you’ve got to protect wildlife as well as tackling climate change.”

According to EDF’s website, the Sizewell C plant “will generate enough low-carbon electricity to supply six million homes” and will avoid approximately nine million tonnes of carbon emissions from entering the atmosphere by replacing fossil fuel power.

Mr Kwarteng has until later in the year to decide whether to grant consent for EDF to build the Sizewell C plant.

The new deadline in July is to ensure there was “sufficient time to fully consider further information provided by the applicant and interested parties in response to the secretary of state’s post-examination consultation”, according to the Government.

In April the Government unveiled a multi-million pound package to bolster its new energy strategy, which they said would “unlock the enormous potential” of hydrogen and nuclear power in the UK.

Speaking at Hinkley Point C nuclear plant in Somerset, Prime Minister Boris Johnson had said: “We’re bringing nuclear home, with one nuclear plant, one nuclear reactor, every year for eight years, rather than one a decade.”

He added: “This is a massively green strategy as well. By 2030, 95% of our electricity will be from low-carbon sources.”

The Government had already announced £1 million in funding to support Sizewell C’s continued development in January.

A spokesperson for Sizewell C said: “Our plans for Sizewell C will lead to a 19% increase in local biodiversity. We are not building on any land owned by RSPB Minsmere. Where a small part of our boundary meets RSPB land, we are creating a new area of wetland to allow wildlife to thrive.

“We will limit construction when necessary to reduce noise and we will use directional and low-level lighting. We are confident our plans will not have an impact on this important nature reserve.”