Nottingham officially moved into Tier 3 at 12.01am today, and new rules will include a ban on buying alcohol from shops after 9pm.
Large groups of young people in fancy dress drank alcohol and chanted near police vehicles on the streets of Nottingham last night - hours before the toughest coronavirus restrictions were imposed on the city.
The gatherings came despite police warning that they would have "no hesitation" in fining those who deliberately flout the rules.
Some of the youngsters appeared to be celebrating Halloween two days early. A few police vehicles were present in the city centre, as well as an ambulance.
Earlier on Thursday, Assistant Chief Constable Kate Meynell said: "Sadly there has been a minority of people who think the legislation doesn't apply to them and we have been forced to take action, and in some cases hand out fines.
"In the last week we have given £10,000 fines to four people who organised parties with more than 30 people present as well as numerous £200 fines to people who wantonly broke the law."