LONDON (AP) — British prosecutors say 15 people who attached themselves to a plane at a London-area airport last year have been convicted of aviation security offenses.

The demonstrators used bolt cutters to create a hole in the perimeter fence at Stansted Airport on March 28, 2017 and then used expanding foam, scaffolding poles and lock box devices to secure themselves to the wheel and wing of a Boeing 767. The plane had been chartered by the Home Office to repatriate passengers to Nigeria, Ghana and Sierra Leone.

Judith Reed of the Crown Prosecution Service said Monday that the group "placed themselves, the flight crew, airport personnel and police at serious risk of injury or even death due to their actions."

The group will be sentenced later.