Celebrity-backed campaigners say they will launch a fresh legal challenge in their “David vs Goliath” fight against onshore transmission planned for Iberdrola’s £6.5bn ($8.5bn) East Anglia Hub in the North Sea.

Suffolk Energy Action Solutions (SEAS) said it will appeal a decision by the High Court in London to reject a judicial review against UK government consent for two substations being built as part of the offshore wind mega-project.

“We have been disappointed before in this battle and successfully turned things around,” said the group, “so we will continue to challenge our case through the courts.”

The campaigners are fighting against the East Anglia 1 North and East Anglia 2 projects. These form about half of the 3GW East Anglia Hub planned in the North Sea by ScottishPower Renewables, Iberdrola’s UK subsidiary.

SEAS says it is not opposed to offshore wind but rather the “catastrophic” impact of the onshore substations. At 14 metres high, the group argues these would dominate the landscape around the medieval village of Friston and coastal town of Aldeburgh, near where the stations are planned.

Their campaign has previously received the backing of celebrities including Hollywood star Ralph Fiennes and local Members of Parliament.

SEAS proposes that much of the infrastructure could be placed on offshore platforms, connected to a single onshore hub in an already developed site nearer London. The group says this would reduce impacts on the environment and local tourism – and would also be around £2bn ($2.6bn) cheaper.

“Belgium, Holland, Germany, Denmark and all other leading wind power countries have embraced the offshore grid model, introducing offshore platforms for pooling wind energy and delivering it to brownfield sites closer to demand,” said SEAS.

“Only Britain is sticking its head in the sand.”

Approached for comment, ScottishPower referred Recharge to its statement earlier this week in which it said it was “committed to delivering these critical infrastructure projects as quickly as possible to achieve a cleaner and greener future for us all.”

It said the wind farms will put “homegrown green electricity” on the grid and deliver billions of pounds in investment, creating a bright future for the region and a positive legacy for years to come.”