### Clue: Perhaps ironic and self-referential leader crossing Old Street, on about communist uprising (10)
### Answer: POSTMODERN 
 ### Explanation: Definition: Perhaps ironic and self-referential
 [ PM(abbrev. for "Prime Minister", government leader in some countries) **containing**(crossing) O(abbrev. for "old") ST(abbrev. for "street") ] + ON **containing**(about) **reversal of**(uprising) RED(a communist).
Answer: Describing the style in art, architecture, literature, etc. that rejects modern thought and practice, featuring elements from previous periods, and with ironic ornamentation and critiqued as contradicting itself through self-reference.