A policeman was hurt after a foiled robbery on a cash delivery van in Lancaster city centre.
Security guards noticed two cars following their Mercedes and alerted police. Both vehicles were quickly intercepted but sped off.
One, a stolen silver Audi TT, registration number MT12EWH, mounted the pavement on George Street, striking the officer who was trying to stop it.
The officer suffered bruising in the incident, at 10.30am on Friday (September 27).
The second, a stolen white Audi A6 estate, registration DU61TXY, drove off down Aldcliffe Road and was last seen on St Michaels Lane in St Michaels village around an hour later.
Lancashire Police are appealing for witnesses who may have seen both Audis and also a man who abandoned the Audi TT on Knowsley Close in Lancaster.
The man is described as white with a weathered face or dark complexion, aged between 30 and 40-years-old, unshaven, with short, dark hair wearing a black front zipped top over a blue t-shirt.
Police said he was last seen running across fields towards the canal in the vicinity of the rear of the Royal Lancaster Infirmary grounds.
DI Phil Jones, of Lancashire Police, said: “I have no doubt that the Greet Team security guard’s diligence and the swift response by the police officers foiled what would have been an attempt to rob the guards of a substantial amount of money.
“Thankfully the officer has only sustained slight bruising as a result of the collision with the stolen car. I would appeal to the public who were in the city centre around 10.30am on Friday to contact Lancaster Police on 101 or Crimestoppers anonymously on 0800 555 111.”