Police have warned that "those who blatantly disregard" the rules will be fined as Covid restrictions relaxed on Monday.
As pubs and restaurants opened their doors again to allow groups of six to be served inside, police chiefs warned they would take action against anyone breaking the rules.
Martin Hewitt, chair of the National Police Chiefs’ Council, said: “The police will continue to play our part in helping the UK beat the virus and will take any necessary action against those who blatantly disregard the remaining restrictions. Anyone attending or organising large illegal parties or unlicensed music events can expect to be fined.”
During the course of the pandemic police officers in England have issued more than 85,000 fines to people flouting Covid restrictions, including on meeting up indoors or in large groups.
But MPs have called for these fines to be reviewed after more than a quarter of prosecutions in the first two months of 2021 for breaching the regulations were shown to have been wrongly brought.
Parliament’s joint committee on human rights recently said the regulations, which have been regularly changed since last March, were confusing and unfair.
A police watchdog said officers sometimes struggled to enforce restrictions throughout the pandemic because of a lack of clarity from government ministers.
Her Majesty's Inspector of Constabulary and Fire and Rescue Services said chief constables first heard about new restrictions from the government’s televised briefings.
From Monday people will be able to meet indoors in groups of up to six or as two households, or outdoors in groups of up to 30 people.
Pubs, bars, restaurants and cafes will be able to serve people indoors, and theatres and cinemas will reopen with limits on capacity in place.
Mr Hewitt said: “While I understand that people are excited to enjoy new activities, as well as seeing more of their friends and family, it really is vital people continue to keep the threat of Covid-19 at the forefront of their minds and stick to following the rules.
“Our officers will continue to carry out patrols and will engage with the public to explain the restrictions which remain in place at the time.”