Archaeologists have warned that medieval artefacts and a 400-year-old farmhouse could be lost in plans to build hundreds of homes in the Vale of Glamorgan.

The Welsh Government is planning on building 576 houses and flats on 60 acres of farmland just south of Penarth, next to Cosmeston Lakes Country Park.

But the plans have drawn criticism over the alleged loss of historical heritage, countryside, and potential increased congestion and pollution in the area.

Jonathan Lambert and his brother Mark, both archaeologists, researched the history of the farm and in an excavation found medieval coins, pottery, and building materials possibly dating back to the 14th century.

They dug three trenches in a field on the farm, on the other side of Lavernock Road from Cosmeston Lakes, where they found the medieval artefacts. They claim that important historical heritage could be lost if the plan to build houses goes ahead.

The plans could also mean demolishing the farmhouse and barn at Lower Cosmeston Farm which are still in use by the current residents. Jonathan Lambert said the farmhouse is 400 years old, while the barn dates back to the late 18th century.

He said: "I had a hunch there was something in the area and in the very first trench I found a lot.

"The farmhouse is one of the oldest buildings in Penarth."

The archaeologists are set to apply to Cadw, the Welsh Government's historic environment service, for the farmhouse and barn to be listed and the medieval remains scheduled — legally protecting the area and its archaeological heritage.

The plans have also drawn criticism from residents living nearby, who are concerned about the impact on the local environment and already-stretched local infrastructure.

Campaigners are objecting to the plans because of the loss of countryside but also because they say the pandemic makes it harder for people to have their say in the planning process.

Michael Garland, chair of Keep Cosmeston Green, said: "We can't deliver leaflets, we can't talk to people on the street, we can't have a proper discussion about it. I wrote to the First Minister asking him to withdraw the application until after the pandemic was over, but that was refused.

"Unless you have a computer, you can't look at the plans online. You can't visit the planning department to see the plans, because you can't travel and the offices are closed anyway. There are restrictions on how you can see the plans and comment on them.

"This land has been farmland for centuries, and it's just going to be lost. There's also a lack of infrastructure. It's just going to exacerbate the road usage, congestion, pollution and pressure on other services in the surrounding area.

"Our road system is inadequate because of the amount of traffic that already uses it. We suffer a lot with congestion. Sometimes trying to get out of our estate can take 10 minutes waiting for a break in the traffic.

"A lot of people go walking over there. It's just nice to be out in the countryside, away from everything. It's the last bit of coastal countryside between Cardiff and Barry. Once they start building on it, it will just be gone forever."

More than 3,000 people have signed a petition urging the Welsh Government to withdraw the planning application. If 5,000 people sign it, the issue could be debated in the Senedd.

Andrew RT Davies, Vale councillor and MS, raised the planning application in the Senedd on October 21. He said: "Do you think it's appropriate that such a major scheme should be brought forward and promoted by the Welsh Government, with the current restrictions stopping public engagement?

"Would the Welsh Government reconsider this application and withdraw it, waiting until a better time so the public can have a fair crack at engagement and consultation over this major proposal for residential development?"

Finance Minister Rebecca Evans MS said: "The land at Comeston will provide a significant contribution to the Vale of Glamorgan's identified housing need. If this proposal doesn't go ahead it's likely that an alternative site will need to be allocated.

"Importantly, representations do need to be made to the council in respect of the application. I would expect that the local authority would find ways to engage with the public and allow them to make their representations with regard to this particular scheme, regardless of the current situation."

After the current public consultation, the planning application will be considered by Vale councillors on the planning committee, who will vote on whether to approve permission for the development. A date for that meeting has not yet been set.

A Welsh Government spokesperson said: "The planning application for a residential development of land at Lower Cosmeston Farm, Penarth, will be subject to a period of publicity and consultation which will enable representations to be made to the local planning authority [the Vale council].

"The planning application is supported by numerous technical reports including archaeological and heritage statements as well as a transport assessment. It will now be for the Vale of Glamorgan council to consider the planning application and any representations made."

A Vale of Glamorgan council spokesperson said: "The council is currently considering a planning application from Welsh Government relating to this matter. The plans can be viewed through the online planning register on the council's website and comments are invited from any interested party.

"Planning officers are available to discuss the proposals with members of the public throughout the normal working week by email, telephone or virtual meeting if necessary.

"Views can be submitted by emailing [email protected] and all will be considered as part of the normal planning process. We will also be using our social media channels to encourage people to share their thoughts on this issue.

"The site was allocated for development in the Local Development Plan, which itself goes through a rigorous examination in public process with community engagement. The LDP was adopted by the council in June 2017."