be down to somebody/something
be down to (one)
To be someone's duty, decision, or responsibility. After your father retires, it will be down to you to lead the company. So I guess it's down to me then.
See also: down
be down to something
COMMON If something is down to something else, the second thing is the cause of the first. When you are asked to score goals, then a lot is down to confidence and Kevin has that. I think that the show's popularity is down to two things.
be down to somebody/something(informal)
1 be caused by a particular person or thing: She claimed her problems were down to the media. ♢ Our defeat in last week’s game is down to the goalkeeper, who played very badly.
2 be the responsibility of somebody: It’s down to you to check the doors and windows before we leave.