The British government has condemned an anti-migrant demonstration in the southern English city of Portsmouth, describing the actions of hundreds of protesters who blocked roads and attempted to prevent asylum seekers from leaving the area as thuggish and intimidating.

The protest, which took place on Sunday night, was the second major anti-migrant demonstration reported in southern England over the weekend. A day earlier, large groups of masked protesters had disrupted access to the Port of Dover.

A spokesperson for the UK Home Office said the government condemned the behaviour witnessed in Portsmouth, stressing that while peaceful protest remains a fundamental democratic right, demonstrations must not descend into disorder or intimidation.

Footage shared on social media showed protesters, many of whom were dressed in black and had their faces covered, confronting police officers equipped with riot shields.

The officers had established a security cordon around buses carrying asylum seekers who were waiting to be transported to a processing facility. Authorities later confirmed that the migrants were successfully moved from the area despite the protest.

The latest demonstrations have nevertheless intensified debate over Britain's immigration policies, the security of the Channel crossing and the government's response to irregular migration.