US idiot's boring digits for Billingsgate workers (11)

'billingsgate workers' is the definition.
The definition and answer can be both people as well as being plural nouns.
Perhaps they are linked in a way I don't understand?

'us idiot's boring digits' is the wordplay.
I cannot really understand how this works, but
'digits' could be 'is' (I is an example) and 'is' is located in the answer.
This may be the basis of clue (or it may be nonsense).

'for' acts as a link.

Can you help me to learn more?