blues and twos

English

Noun

blues and twos pl (plural only)

1. (chiefly UK, Ireland, informal, law enforcement) The flashing blue lights and (originally) two-tone siren of a police vehicle.
   • 2019, Kate Atkinson, Big Sky, →ISBN, page 112:

     They grinned at each other and hit their blues and twos.

Further reading

• blues and twos on Wikipedia.Wikipedia