Kyron Marshall, 33, had made the call, saying that he was having thoughts of harming himself and others, the city’s magistrates’ court was told on Monday.
Prosecutor Paul Brown said: “They attended the flats and saw Marshall on the footpath.
“They asked Marshall to show them their hands.
“They produced a kitchen knife with a four to five-inch blade. They were told to drop it and they immediately complied.
“Police have then property in their bag and found four other kitchen knives.”
The incident last Saturday was at Viersen Platz. Marshall, of Loire Court, pleaded guilty to possession of knife blades in a public place and a separate charge of sending a threatening message to Cambridgeshire Constabulary on December 6.
The court was told that he was on a suspended sentence order of 14 months when the offences took place.
Solicitor Claire Thorneley said her client was “well aware” of the mandatory minimum custodial sentence for a second offence of knife possession.
There was no application for bail and Marshall was remanded until a sentencing hearing at Peterborough Crown Court on a date to be fixed