Officers say the 71-year-old passed out when she fell back and hit the pavement after being struck in the face as she tried to help break up a brawl in Ormskirk town centre.
Detective constable Michael Feeley from West Lancashire Criminal Investigation Department said: “It is utterly disgusting to think that an elderly woman, just acting as a pacifist, was punched so hard she landed on the pavement and was knocked unconscious.
“We are investigating the full circumstances around the altercation between the groups, the woman being attacked and the man being hit by the car.
“If you recognise the man pictured or you have any information that could assist without inquiries, please make contact with us.”
The fight, which broke out at around 11pm on Saturday evening, involved two groups of men throwing bricks at each other in the Wheatsheaf car park near Railway Road.
The street pastor spent the night in hospital and has been recovering at home.
Dave Mutch, co-ordinator of Ormskirk Street Pastors, told Premier: “She [the victim] was not breaking up a fight, as incorrectly reported in a number of newspaper articles, but was simply walking through a public thoroughfare when she suffered an unprovoked attack.
“This is the first such incident that Ormskirk Street Pastors has encountered since we started our patrols in January 2011.
“We will continue to ‘Listen, Care and Help’ people on the streets of Ormskirk every weekend.
“The police are investigating the matter; please contact them if you have any information in connection with this attack.”
Stay up to date with the latest news stories from a Christian perspective. Sign up to our daily newsletter and receive more stories like this straight to your inbox every morning.
Lancashire Constabulary has released a picture of a man they want to speak to after an elderly street pastor was left unconscious after being punched while on duty.