The British government announced in April it had struck a deal to send potentially tens of thousands of asylum seekers to the East African nation in a bid to smash people-smuggling networks, and stem the flow of migrants risking their lives by crossing the Channel in small boats from Europe.

The first flight taking the migrants to Rwanda was expected next week on June 14, the government has said.

"It's vital that new Government policies respect and uphold the laws that we all, as a society, have agreed to follow," said James Wilson, Deputy Director of Detention Action. "That's why we're seeking an injunction to keep this plane to Rwanda from leaving the runway."

(Reporting by Michael Holden. Editing by Andrew MacAskill)