blues and twos
An emergency vehicle, such as an ambulance or police car, that has blue flashing lights and a siren that sounds two notes. Primarily heard in UK. Pull the car over and let the blues and twos pass.
blues and twos
the siren and blue flashing lights of an emergency-service vehicle. British informal The twos refers to the vehicles' two-tone siren.
2003 Bolton Evening News They will go out with local officers and really learn the craft of being a beat bobby rather than just going out in blues and twos.