Diamonds stolen from transport in London? It's a puzzle (5)
I believe the answer is:
rebus
'a puzzle' is the definition.
(type of visual puzzle)
'diamonds stolen from transport in london? it's' is the wordplay.
I cannot really see how this works, but
'transport' could be 'bus' (bus is a kind of transport) and 'bus' is present in the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is present in the answer.
A single letter 'r' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for rebus that I've seen before include "Pictorial word puzzle" , "Picture-puzzle" , "Pictorial wordplay" , "Word puzzle with pictures and letters" , "Ian Rankin's Scottish detective" .)
