"We are looking at the potential use of military and non-military use sites for temporary accommodation for the people who come across on these small boats," Defence Secretary John Healey told Sky News.

Interior minister Shabana Mahmood said in a statement migrants using boats to cross the Channel from France was "utterly unacceptable".

More than 30,000 people have arrived by that route since the beginning of the year, according to figures published Sunday by Mahmood's Home Office.

She also said a deal with France that came into effect in early August should allow Britain to detain those arriving by boat and send them back to France.

The agreement allows the returns as long as Britain takes in an equal number of eligible migrants from France.

Protests have erupted around some of the hotels currently used to house migrants, with the government having to fight legal challenges.

The government is legally bound to ensure access to accommodation and to health care for asylum seekers.

Prime Minister Keir Starmer has pledged to end the use of hotels within the next four years, and his government has already announced that the number of places has been halved compared to a year ago.

The previous Conservative government had already set up two disused military bases which are accommodating several hundred asylum seekers -- a practice criticised by migrant-aid groups.