The Labour-run Northumberland County Council is proposing to build a new supermarket, retail units, drive-thru restaurant and a pub on the County Hall site in the town.
As part of the controversial plans, the land has also been earmarked for housing and the new Morpeth First School.
It comes as the authority is set to leave its Morpeth base in 2019 when staff move to a new £32million headquarters in Ashington.
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But the plans, which are expected to go in front of the council’s planning committee in March, are facing mass opposition after more than 1,557 individual letters of objection have been lodged from residents and businesses against the proposed development.
Major concerns include the impact of the end-of-town retail park on the main town centre and claims that the scheme is contrary to the Morpeth Neighbourhood Development Plan.
And today, objectors showed the strength of feeling against the scheme, as people turned out in huge numbers for the demonstration.
The march, organised by Morpeth Chamber of Trade, started in Morpeth market place at noon and finished at County Hall.
A copy of the Morpeth Neighbourhood Plan was left in the main reception for the attention of the authority’s planning team.
The county council has said that all views and responses will be taken into account when the final decision is made.
Speaking at the protest, Coun David Bawn, ward member for Morpeth North, said: “There is a major upswell of opinion against these plans to build houses and retail on this site. The number of people on the march shows the strength of feeling and let’s hope the council pays attention.”
Coun Andrew Tebbutt, ward member for Morpeth Kirkhill, added: “It was an absolutely fantastic turnout and the people of Morpeth have given a very clear message to the Labour administration that they don’t want their plans. They don’t want their housing plan, they don’t want their retail plan and they want the school in a proper place. I hope they will listen.”
Northumberland Conservative group leader Coun Peter Jackson said that people in Morpeth feel that the plans are ‘immoral’.
After the protest, chairman of Morpeth Chamber of Trade and organiser of the march, Jacky Beesley, said: “I would like to thank Morpeth residents and businesses for turning out in such numbers.
“Will the penny now drop with the Council Leader, Grant Davey, that these plans will destroy Morpeth as a market town and town-centre businesses?
“A report commissioned by the council makes clear that £1 in every £4 will be lost from the town centre’s main retailers and such a drop in footfall would decimate the smaller retailers.
“Chamber members and smaller national retailers have told me that they simply could not absorb a reduction in trade of this magnitude, and store closures and job losses will result.
“There has been opposition from when the plans were first presented last November, but the administration has buried its head in the sand, and unbelievably the Leader has continued to publicly support them. It’s about time that the residents and businesses were listened to and respected.
“Any future retail development could and should be in the town centre. An edge-of-town retail park and a small market town do not mix.”
David Holden, of South Morpeth Coalition, said, “What a fantastic turnout with residents prepared to take time out of their working day or half-term holidays to show again how unpopular these plans are.
“The housing scheme is simply not required with planning permission already in place for nearly 3,000 new houses in Morpeth. This will increase the size of the town by 40 per cent with Morpeth not having the infrastructure to cope.
“This increase is way above the numbers stated in the local plan and does not justify building on protected open space and the route of a future strategic link road.
“The concerns of the chamber of trade are well-founded and there is a misconception that the retail proposal is a parade of local shops.
“It includes a supermarket, pub and a number of large retail units but most tellingly, it has a car park with 336 spaces, which is the same size as the town centre’s main car park.
“It is a competing retail centre, and like the housing, it is contrary to the Morpeth Neighbourhood Plan and should be refused by the council’s planning officers and the planning committee on March 7.
“If these proposals are approved, people may well conclude that there is something fundamentally wrong at Northumberland County Council.”
A spokeswoman for the county council said: “As we have said previously, all views and comments made in response to the planning applications will be taken into account by the Strategic Planning Committee in due course.
“The Government is clear that Neighbourhood Plans are not there to prevent development from taking place, but can influence where new development is located, and the design, layout and materials used.
“Neighbourhood Plans can help to ensure that new development is sympathetic to the surrounding area and meets the needs of the local community.
“The applications will take into account the Morpeth Neighbourhood Plan, saved policies of the Castle Morpeth Local Plan, as well as being considered against all relevant national and local planning policies.”