Entrusting the key to a thief!

[suchithrakr]

Is there any English idiom or phrase which conveys the meaning "entrusting the key to a thief"?

[BobK]

I can't think of one directly, but an ex-thief who is entrusted a key is called 'a poacher turned gamekeeper' (for example, a computer hacker who becomes an adviser on network security, or a government tax officer who becomes an accountant specializing in tax).

b

[Ouisch]

Perhaps "putting the fox in charge of the henhouse."

[BobK]

Perhaps "putting the fox in charge of the henhouse."

Doh! Of course - that's it. I've also seen 'Putting King Herod in charge of Mothercare', but in the context (a rather intellectual newspaper article, or maybe a chat show) it was just a journalistic flourish; it may catch on, but I wouldn't call it an idiom yet.

b