Hundreds of protesters are intending to block all six entrances to Devonport Naval Base and the adjoining dockyard on November 1.
The protest, which organisers describe as a non-violent event, will see anti-nuclear activists from across the country descending on Plymouth.
They are campaigning to highlight the cost of replacing Trident, which is Britain's nuclear deterrent.
The Trident missile defence system is carried on four Vanguard-class submarines.
Devonport is the UK's only base with the specialist facilities and skilled workforce to maintain the submarine fleet.
Meanwhile government departments are still thrashing out details of how the controversial system will be funded.
The coalition Government is planning to renew the system, but the Ministry of Defence and the Treasury departments are at loggerheads about which will foot the multi-billion-pound bill.
Plymouth-based defence expert Iain Ballantyne has warned that placing Trident in the MoD's budget would effectively 'mean the end' of the armed forces with little or no money left to maintain the strength of the Royal Navy, Royal Marines, Army or RAF.
New missile system a waste of money
A CITY campaign group believes the Government should scrap the controversial Trident missile defence system and pump the money into the economy.
Shirley Law, a Plymouth-based Trident Ploughshares campaigner, says in today's economic climate, and with a diminishing threat of nuclear strikes against Britain, there is "no point" in renewing the £20billion deterrent.
"When you think how bad the state of the economy is, and then you consider the politicians are looking to spend £76billion on replacing Trident, it makes no sense," Mrs Law said.
"In this climate it is a huge waste of money and we just don't want it any more. The greatest risks to us today are global warming and terrorism. Trident will not help either of those issues."
Mrs Law was speaking as Trident Ploughshares announced plans for a huge protest in Plymouth on November 1.
The protest to highlight the cost of replacing Britain's nuclear deterrent will see campaigners blockade all six of the gates at Devonport Naval Base and the adjoining dockyard.
Up to 400 protesters are expected to attend the non-violent protest.
Mrs Law added: "For Plymouth, this will be the biggest blockade we have ever staged.
"We are expecting at least 300 or 400 people and we will blockade every gate at the site. We want to make people stop and think about the stupid idea of replacing Trident.
"We also want people to consider the proposals to scrap nuclear submarines in Plymouth. There is no point in complaining after these things have been decided on. We need to be heard now."
The blockade will start at 6am on November 1.
During the event campaigners will be distributing leaflets and displaying posters highlighting the cause.
On its website, Trident Ploughshares states Plymouth is becoming known as the 'Sellafield of the South West' because of its involvement with nuclear submarine refits, maintenance and upgrades.
Sarah Lasenby, a member of Trident Ploughshares, said: "This could well be the largest blockade ever staged. In many ways it should be, given the strength of feeling towards Trident right now."
Plymouth's blockade follows a disarmament camp in Aldermaston in February which attracted about 1,000 people. Last November about 300 people attended a rally in Devonport protesting against proposals to scrap nuclear submarines at Devonport Dockyard. The event was organised by the Campaign for Nuclear Disarmament.
An MoD spokesman said: "We respect everyone's right to peaceful and lawful protest. The Royal Navy has an excellent safety record in the operation of its nuclear submarines."
Rebuild delays could bring benefits
DELAYING the replacement of Britain's nuclear deterrent system could lead to lucrative work at Devonport Dockyard, supporters claim.
While the coalition Government's Treasury and Ministry of Defence departments do battle over which will fund the £20billion replacement, many believe Plymouth in particular could benefit.
The Government has confirmed it will keep and renew the Trident missile defence system, which is carried on four Vanguard-class submarines.
With Devonport being the UK's only base with the specialist facilities and skilled workforce to maintain the submarine fleet, any delay building the new fleet would mean Plymouth once again having to refit one or more of the boats.
These refits are worth hundreds of millions of pounds to the city's economy. While this could be viewed as a positive scenario, others aren't quite so good.
One of the proposals to cut future costs is to reduce the number of Trident-carrying submarines from four to three. This would take away one of Devonport refits.
This decision, coupled with the looming Strategic Defence and Security Review which new Defence Secretary Liam Fox has warned could be 'the absolute mother of horrors of a spending review', could have huge implications for the city.
Gary Streeter, Tory MP for South West Devon, said it is important the correct decision is made to fund a replacement system.
"The decision has been made to keep and renew Trident," he said.
"The problem is where the money will come from to renew it.
"There'll be a knock-on effect if the MoD is forced to cover it. We need to make sure the outcome of the review is the correct one. I think the Treasury will have to find a way to fund part of it."
Alison Seabeck, Labour MP for Plymouth Moorview — who now sits on the influential Defence Select Committee — said the issue is "impossible to call" and believed an announcement on Trident will be made later this month.
Roger Darcy, chairman of Devonport Dockyard's industrial trade unions, said concerns among workers had not diminished.
"We've heard rumours, including the one about extending Vanguard's life," he said.
"That would be a good thing, but then we hear the MoD's being told to cut 20 per cent from its budget.
"We rely on workloads from the MoD, so there's still that concern."
Plymouth-based defence expert Iain Ballantyne said the future of Trident would depend on how ruthless the Government wanted to be.
"If Trident is placed within the MoD's budget they might as well turn off the lights on the UK's armed forces," he said.
"Trident would blow the budget apart and mean the end of the armed forces."
He added: "Delaying the replacement would help to retain skills in Devonport and give us another multi-million-pound refit."
But Sarah Lasenby, of Trident Ploughshares, said the campaign group would like to see Trident scrapped altogether.
"It's a devilishly expensive thing and the money would be far more use elsewhere in society," said Mrs Lasenby.
Details of the Strategic Defence and Security Review are expected this autumn.