The cutlery is a mess (7)
I believe the answer is:
canteen
'mess' is the definition.
(both can mean a room for eating)
'the cutlery is a' is the wordplay.
I cannot really understand how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found in the answer.
'a' could be 'an' and 'an' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for canteen that I've seen before include "Cafe, flask and cutlery box" , "Refectory" , "Workplace restaurant" , "Workers' cafe and cutlery box" , "Works'' restaurant - cutlery" .)