Between the devil and the deep blue sea

47 Meters Down is a cautionary tale for all daredevils planning their summer holidays.

An underwater survival thriller, it is also a B-movie that efficiently does what it sets out to do - provide silly escapist scares - within 89 minutes.

Mandy Moore and Claire Holt are Lisa and Kate, the American sisters on vacation in Mexico invited by two local guys to go cage-diving.