A car rammed a police van after it fled patrols near a pub in in Preston City Centre, say police.
Operational Support Officers say they tried to stop and speak to the driver of a black Toyota Auris to the rear of the Adelphi Pub in Adelphi Street at around 4pm on September 1.
The driver is then reported to have reversed almost crashing into two police officers.
Police say the car smashed into the police van causing damage and drove off at speed, however officers did smash the car's window as it escaped.
A spokesman for the police said: "The beer garden of the pub was busy at the time and we appeal for any witnesses who might be able to name the driver to come forward.
"Likewise, anyone who may know someone who's been involved in any way. Callers can remain completely anonymous."
Anyone with information can contact PC 4075 Plummer on 07815 448321, or alternatively contact police on 101 quoting reference 0991 of 01/09/17..