S1·E15 Aldwych Underground Station

Yvette and Jason don 1940s army uniforms to get into the feeling of Aldwych Station, which was built after the demolition of a theatre in 1907 and used as an air raid shelter in the Second World War. Derek speaks to a ghost called Margaret, who claims she was an actress and has been sighted many times before. As the crew walk through the tunnels in pitch black, Yvette thinks she sees a figure in the tunnel. Meanwhile, over another platform, a motion detector is set off yet nobody is near enough to trigger it...