Wiktionary
asleep at the switch
a. (context idiomatic English) neglectful of an important task, responsibility, or opportunity.
Usage examples of "asleep at the switch".
Somebody in the quality control department at the jolly old Ovril factory had been asleep at the switch.
The ones who had their backs to the action, or were just asleep at the switch, had to rely on dumb luck for survival.
The Lizards inside Lakin hadn't been asleep at the switch, either.
You're working with a new screener who falls asleep at the switch just when you remember something you heard once about how to make brain viruses, and a Weaver possesses the man you're interviewing and kills you on the spot.
The police haven't been entirely asleep at the switch, and you left something of a back-trail yourself.