Dear MI-5 Fans:
Regretfully MI-5 Season 4 has been removed from the schedule due to failure to attract a significant audience. As you all know, it's a reality of ad-supported television that networks often have to change their schedules due to ratings.
Of course, we value the fans who have supported the show, and we've been really proud to air it on our network.

Sincerely,
BBCAMERICA.com