Police had to close Preston Flag Market after claims that the city council failed to grit the surface during freezing weather.
More than a dozen shoppers, including a pensioner who had to be taken to hospital, slipped on the stone flags on Saturday.
Judith Davidson, a receptionist at the Specsavers branch in Friargate, said she saw around 18 people fall on the market.
She said she nearly fell when walking to work and likened the conditions to an ‘ice-skating rink’.
She said: “It was terrible. We had two of the girls go out of the shop advising people not to walk on the Flag Market because it was that slippy.
“We had one lady taken to hospital, in her 70s or 80s. That was about 10.30am.”
Optical assistants Becky Wilson and Kirsty Serdiville tended to the lady and warned others not to cross the area.
Becky said: “It was really, really bad. People were flying everywhere.
“Kirsty went over and somebody had got the lady a chair. She smashed her glasses so we repaired them for free.
“Later on a guy came from the council and put down some grit. I said ‘you should have been out at 7am putting the grit down - that’s why people pay their taxes’.”
Judith said she rang Preston Council and was told gritting was Lancashire County Council’s responsibility, but when she rang county hall she could only get through to an out of hours answer machine, and turned to the police instead.
Gritting the Flag Market is in fact the responsibility of Preston Council.
Special Sgt Kevin Kellett, who attended the scene, described the stone flags as “unwalkable.”
In an email sent to Preston Council and local councillors, he asked for an investigation into why the Flag Market had not been gritted when icy conditions were forecasted.
Staff Sgt Kellet said: “Apart from a small section near the cenotaph there had been no gritting of the flags.
“When my attention was brought to this issue, at approximately 11am, various people had already been taken to Royal Preston Hospital due to their injuries and others had suffered falls and minor injuries.
“I immediately requested that Preston Council turned out to grit the area but by the time the ice had melted, at approximately 12.30pm, nobody from the council had turned up.”
He said that the council should send letters of thanks to the Specsavers staff and to Solomon Raj, Stephen, Lydia and Rosie Warning, Frank and Pat Riley and Balaz Kovcs, all from New Beginning Ministries in Stour Lodge, Fulwood, who spent two hours preventing people from walking on the flags to make sure there were no more injuries.
He said: “I honestly do believe that Preston Council and the people of Preston owe these volunteers a huge debt of gratitude.”
However, Preston Council said it had gritted the area.
A council spokesman said: “Staff did attend and put grit down at the Flag Market area after 8am. It seems there was one area of the Flag Market that may have been in shadow and did not thaw out as it was very cold during the day.
“This can happen even when grit is put down and we would always ask members of the public to take care when travelling in icy conditions.
“We would like to thank those volunteers who warned others of the conditions.
“We are in discussions with Lancashire County Council about future gritting in this area as part of it belongs to the public highway.”