Downing Street denied the government was involved when the charge was announced. A spokesman said: “No – charging decisions and when they are made are for the CPS.”

Ms Cooper warned against speculating about the case, adding: “The most important thing is to get justice for Bebe, Alice and Elsie and their heartbroken families and everyone affected by the attack, and no one should put this in jeopardy.”

Jonathan Hall KC, the independent examiner of terrorism legislation, said authorities should be more open about information from terrorism cases to avoid an “information gap” that could be exploited by people on social media.

Mr Hall told BBC Radio 4’s Today programme: “The police and the CPS are operationally independent and it is important that they are. And if the police and the CPS say “we really don’t think you can put anything in the public domain anymore”, I think the Government should be affected by that.

“On the other hand, I also think the Government needs to be aware and will be aware that if there is an information gap, particularly in the mainstream media, then there are other voices – particularly in social media – who will try and fill it.

“I would always say to the Government … if there’s information you can give, put it in the public domain and be really careful not to fall into the trap of saying, ‘We can only say smile because there’s a criminal trial .’

“Quite often there is a fair amount of information that can be put into the public domain and I think I detect that the police are trying to do that. They realize now that just saying ‘there’s a fee, we can’t say more’ isn’t going to cut it these days.”