The controversial new distribution site, which would be built on land in Patcham Court Farm in Vale Avenue, Brighton, would include new storage facilities and a vehicle maintenance facility.
However, campaigners from Patcham Against Royal Mail have raised concerns that the development would put an aquifer used for Brighton’s drinking water at risk of contamination.
Concerns have also been raised by residents over increased traffic and pollution that the development would bring, as well as the threat to the conservation and heritage site.
Around 160 people gathered at the proposed development site, holding placards that said “save our aquifer”, “stop Royal Mail” and “Patcham village will not benefit”.
Protesters also chanted “save Brighton’s water” and held a minute’s silence for the potential loss of the aquifer.
Among those taking part in the protest were Conservative councillors for Patcham Alistair McNair and Anne Meadows, along with Green Party candidate for Brighton Pavilion Sian Berry.
Ms Berry shared concerns about the future of the aquifer if the plans are approved and said: “The water supply is already on the edge in terms of pollution from nitrates so you cannot take the risk with a new development.”
Cllr Meadows said it was “amazing” to see the strength of support to protect the city’s water supply.
She said: “People think this is Nimby-ism but it is nothing to do with that. We’re protecting the water supply for the city and protecting our heritage.”
Cllr McNair criticised Royal Mail for lack of consultation of residents on the issue, which he said will affect people across the city due to the effect on drinking water.
“They could come here and answer people’s questions and be direct and honest but they haven’t bothered as they’re not interested,” he said.
Cllr McNair also urged the Labour administration to ensure the voices of residents are heard on the subject.
He said: “The Greens and the Conservatives are listening to residents – will Labour?”
Mike Howard, who co-chairs the campaign, said even the slightest amount of pollution at the aquifer could cause all of Brighton and surrounding areas to have their water supply switched off.
He said: “If a litre of oil spilt on the ground it would contaminate one million litres of drinking water from here to Brighton to Peacehaven and the equivalent distance the other way.
“Imagine if, during the construction phase, one of the hydraulic lines on a digger fails – which does happen. They will have to shut off all the drinking water for this area – I’m not exaggerating and I don’t know how long that would have to last.”
His message to the council’s planning team and to Royal Mail was simple: “Answer the questions we’re posing.”
Comments and objections can be made on the council’s website.