Plans for a network of radars tracking deep space activity to help protect the UK from “space warfare” are to go ahead in Pembrokeshire, despite the opposition of local campaigners.

The 27 radar dishes planned for the St Davids peninsula, which will be 20 metres high and can track objects as small as a football, are part of a network planned around the globe.

The Deep Space Advanced Radar Capability (Darc) will be developed at Cawdor barracks in south-west Wales by the Ministry of Defence. Ministers have said the plans are crucial as long-term defence against the possibility of threats in deep space.

The plans to redevelop the barracks, which were previously set to close, are part of the Aukus defence partnership between the UK, US and Australia. They will involve a network of ground-based radars in all three countries designed to monitor, track and identify objects up to 22,000 miles (36,000km) away from Earth.