https://www.bbc.co.uk/news/uk-england-manchester-48678526A former National Counter Terrorism Co-ordinator has told the BBC the government is not doing enough to ensure that venues are secure.
Nick Aldworth has warned new legislation is needed to reduce the impact of any future attack.
He is supporting a campaign for more rigorous checks at venues, under the name Martyn's Law, after Martyn Hett, a victim of the Manchester Arena attack.
He said such a law could have prevented the spate of attacks in the UK in 2017.
At the time, Mr Aldworth was a Metropolitan Police chief superintendent in charge of keeping Londoners safe.
"People died on my watch when I was responsible for trying to keep London and, more subsequently, the UK secure," he said.
"That's a burden that I will carry."
He said new legislation would help to stop that happening in the future.
"I think without it we have the potential for places to be attacked and for the potential for the effect of those attacks to be far worse than they need to be."
'Reckless and negligent'
At the moment, venues such as theatres, cinemas, and concert halls do not have any legal obligation to put counter terrorism security in place, or to plan for what they would do in the event of an attack.
"I think that without being specific - because there are coroners' inquests under way at the moment - I think there are definitely some places that could have benefitted from some infrastructure," Mr Aldworth continued.
"But one of the things I was told after one of the attacks by a survivor... was she was in a restaurant and nobody knew what to do."
Many places do have bag checks and security screening but Mr Aldworth said it was not the case everywhere, and that some venues were "reckless and negligent".