"Ticketless, drunken and drugged-up thugs" could have caused death as they stormed Wembley before the Euro 2020 final, says a review into the disorder.
The report by Baroness Casey said there was a "collective failure" in planning for the match, which about 2,000 people got into illegally.
It noted 17 mass breaches of disabled access gates and emergency fire doors.
Lady Casey said the "appalling scene of disorder" as England played Italy led to a "day of national shame".
- England given one-match stadium ban following unrest at Euro 2020 final
- Euro 2020: Met denies Wembley police operation failed
- Euro 2020 final: Harry Maguire's father suffered two suspected broken ribs
- Euro 2020: More people sought over Wembley final disorder
Her report said there was a "collective failure" in planning for the match on 11 July, including a "vulnerable" stewarding operation lacking experience partly because of the pandemic and the police deployment arriving "too late".
The knowledge that about 25,000 of Wembley's 90,000 seats would be left empty because of Covid restrictions contributed to a "perfect storm" of factors.
"Our team of role models were in our first major final for 55 years. However they were let down by a horde of ticketless, drunken and drugged up thugs who chose to abuse innocent, vulnerable and disabled people, as well as police officers, volunteers and Wembley staff," said Lady Casey.
"We are genuinely lucky that there was not much more serious injury or worse, and need to take the toughest possible action against people who think a football match is somehow an excuse to behave like that.
"I am clear that the primary responsibility for what went wrong at Wembley that day lies with those who lost control of their own behaviour."
The Metropolitan Police made 51 arrests connected to the final, 26 of which were made at Wembley, and says its investigation is ongoing.
"Detectives are assessing tens of thousands of hours of CCTV footage, body worn footage and social media clips to identify those responsible for the scenes of disorder," it said in a statement.
In all, there were 90 football-related arrests of England fans at Euro 2020.
Italy beat England on penalties to become European champions.
The review into the disorder on the day also found that:
- An England victory in the shootout would have created a "further huge public safety risk" with up to 6,000 people planning to storm the stadium at full-time to celebrate as the gates opened to allow ticket-holders to leave.
- There was "a collective failure" among the organisations who staged the final to plan for the "foreseeable risk" of disorder and ticketless fans converging on the stadium.
- Alcohol and drugs were a key factor in the disorder as fans arrived at the stadium up to eight hours before the 20:00 BST kick-off.
- Planning for the final was hampered by the extra strain placed on authorities by managing the Covid-19 pandemic restrictions and the loss of experienced stewards.
- The Wembley Stadium safety officer made "significant and exceptionally brave" decisions around unchecked access and locking and re-opening turnstiles, without which there would have "likely" been "considerably more injuries or even fatalities".
What does the review recommend?
In the foreword of her report, Lady Casey says: "One of the saddest parts of this process has been hearing the testimony of FA staff.
"While they did not want the England team to lose that night, such was their concern for what might happen in the event of an England victory, they ended up with a feeling of huge relief at the result.
"In the end the penalty shootout went Italy's way, the rain came down, and the crowds dispersed largely quietly. But we should not lose sight of how close the alternative was. And they should never have had to feel that way anyway."
Lady Casey concluded that "law-abiding fans, our national team and our national game deserve better" and that the events of 11 July "can't be allowed to happen again".
She said the absence of fan zones close to the stadium were "potentially a very significant factor" in the situation spiralling out of control, and that the ban on drinking on London transport was not enforced strictly enough.
The national euphoria and focus on the final made fans gathering and disorder "foreseeable" and "there was a collective failure to plan for the worse-case scenario".
Lady Casey wrote: "Finally, the biggest challenge I lay down is around the culture that led some individuals on the day at Wembley, and in the days after on social media, to choose to behave in this way.
"What makes people believe that it is somehow acceptable to break into a stadium or abuse disabled entrances just because it is a big match or there are spare seats inside?
"Why on earth should black footballers be expected to continue to play for their country amid racist abuse from their own countrymen?"
Marcus Rashford, Jadon Sancho and Bukayo Saka were racially abused on social media after the game.
Lady Casey recommends a series of more general changes to help prevent a repeat:
- Empowering authorities to act more strongly against fans using drugs, flares and smoke bombs at matches and around stadiums and entering stadiums without a ticket.
- A Football Association campaign to force "a sea-change in attitudes towards supporter behaviours".
- Better communication between the agencies overseeing the match and the flow of fans to the stadium.
- A new category for football matches "of national significance" to make organisers aware of the unique challenges of such major events.
England have been ordered to play one match behind closed doors and the FA fined 100,000 euros (£84,560) by European football governing body Uefa as punishment for the unrest.
UK Sport has denied that England's possible bid to host the 2030 World Cup has been irrecoverably damaged by the disorder.
What was the reaction?
Football Association chief executive Mark Bullingham said that "no event is set up to deal with such disgraceful behaviour from thousands of ticketless fans", but apologised "for the terrible experience that many suffered within Wembley on what should have been a historic night".
"We fully accept the report's findings and there are important learnings for us, as well as other agencies involved," he added. Collectively we must never allow this to happen again."
Lady Casey, speaking to the media after the publication of her report: "There is no easy target going to be had at Wembley again... in fact, there is almost a danger they will over-police it. That message needs to go out to any thug who thinks they can take on Wembley stewards again.
"If it had only been alcohol I don't think people would have been able to sustain themselves. To go from nine in the morning, 12 in the morning, and for 6,000 people to stay on those steps, outside for the entire match. I think drugs is a significantly greater issue than probably people have realised."
Metropolitan Police Service Commander Rachel Williams: "I am deeply sorry that so many people who came to enjoy a day of football, were met with unacceptable scenes of disorder.
"This moment of national significance was tarnished by groups of ticketless, anti-social and thuggish football fans who were intent on causing disorder and committing criminal acts. We regret that we were not able to do more to prevent those scenes unfolding."
Julian Knight MP, chair of the Digital, Culture, Media and Sport committee, said: "It is clear that we narrowly averted disaster on a major scale at Wembley. This day of national shame saw the behaviour of drunken and drugged-up thugs put the lives of genuine football fans at serious risk.
"That a collective failure in planning allowed safety breaches on this scale is a grave charge given that the risk was foreseeable.
"We must see action taken by football authorities before we bid for any major tournaments. The DCMS committee will be monitoring not what is said today but what is done in the weeks and months ahead."
A Government spokesperson said: "The Casey Report rightly highlights that responsibility for the reckless and criminal behaviour at the Euro 2020 final lies with a small minority of individuals who sought to undermine the day for the overwhelming majority of genuine football fans at Wembley Stadium.
"The UK has a long and successful record of hosting major international sporting events, and the government will now work with the police and football authorities to consider the report's recommendations in full and ensure lessons are learned."
A statement from Brent council said: "We welcome Baroness Casey's detailed and balanced report. This is not about a blame game, this is about learning lessons to ensure that the shocking scenes of Euro Sunday can never be repeated. We will work closely with partners, including the FA and Metropolitan Police, to take forward the recommendations."
Fan accounts: 'One group of 10 mates in our row - all snorting cocaine'
BBC Radio 5 live spoke to several fans after the report was released:
Paul: "It was sort of warzone conditions outside Wembley Park. Broken glass, drunkenness, open drug-taking the likes of which I've never seen before and it was an extremely worrying situation to walk into. It really put a downer on what was going to be a great day.
"With all the issues around the disorder, stewards were diverted to that and there were no searches of bags or anything as you went through the turnstiles. Anything could have been brought in at that point."
Tom: "All the stairs were blocked up, the fire exits were blocked. In our row there ware a group of 10 mates none of them had tickets, all of them were snorting cocaine. It felt very very dangerous."
Tony: "Outside the semi-final was awful as well. That was a lesson that should have been learned by the authorities to have bolstered security up for the final. It was poor for the semi-final but absolutely diabolical for the final.
"For so many years I've been following England and this was meant to be culmination of all of that but it was just such a let down."
John: "The first thing that we saw that really shocked us - the Covid app had stopped working and people were just flashing their phones [to the stewards]. There was a guy in front of us who showed them an email from Argos, that got him in."
Alistair: "It was clear that the people who were organising security around the game and around Wembley don't understand football.
"The magnitude of the occasion as we progressed further and further through the tournament… Anyone who follows football regularly could see that this was going to happen and yet the security layout was almost identical from those first group games all the way through to the final."
'This was dicey... it was scary'
BBC sports news correspondent Natalie Pirks
I've been to hundreds of matches at Wembley in my two decades of being a sports broadcaster. This was dicey... it was scary. It felt like nothing I've ever experienced before.
I would always have said in the past that I'd take my children to England matches but I was so very glad that they weren't there that day.
It was very evident from about 10am that there were no police around. There were fans that were already drunk and worse, and there was no-one around. It does say in the report the police didn't start getting there until about noon, and at that time there were already a lot of fans on the ground.
From 1pm onwards, given it was an 8pm kick-off, you knew what that would entail in terms of drinking all day - but it was so much worse. Flares going off, drug-taking in the streets, lamp posts being bent over, fighting.
When you go abroad with England, you see certain England fans who are very respectful of the culture, they enjoy being with England and are very respectful generally of the country. The fans that you saw that day are not necessarily those England fans.
- The Football News Show: A brand new look at today's top football stories
- Peaky Blinders: The entire season 1-5 boxset is available to watch now