Around 4,000 people gathered for one of the Saturday night events where a 20-year-old man died of the suspected overdose, according to Greater Manchester Police.

Another 2,000 turned out for a second party which saw three separate stabbings, including one which left an 18-year-old man with life-threatening injuries, the force said.

Officers responding to that rave were met with violence from revelers, with items thrown at them and a police car vandalized, it added.

"These raves were illegal and I condemn them taking place -- they were clearly a breach of coronavirus legislation and guidelines, and have had tragic consequences," said assistant chief constable Chris Sykes.

"Coronavirus is still a threat and we will continue to engage with people to encourage them to take some personal responsibility and do the right thing."

Britain introduced a nationwide lockdown in late March to try to stem the transmission of the virus, as the country became one of the worst impacted by the COVID-19 pandemic.

The government has registered nearly 42,000 deaths of those who had tested positive for the disease.

The stringent stay-at-home order has only been gradually eased since late March, with gatherings of up to six people permitted outside, in parks or in private gardens, in England.