Downing Street has denied interfering with the timing of the Government’s impeachment announcement. A spokesman said: “No; charging decisions and when they are made are within the CPS’ jurisdiction.”

Ms Cooper warned against speculation about the case, adding: “The most important thing is that justice is delivered for Bebe, Alice and Elsie and their heartbroken families and everyone affected by the attack, and no-one should risk that.”

Jonathan Hall KC, the independent reviewer of terrorism legislation, said authorities needed to be more open about information in 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 CPS are operationally independent and it is important that they do so. And if the police and the CPS are saying ‘we really don’t think you can put more in the public domain’ I think the Government should be impressed by that.

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

“I always say to the government… if you have information you can give, make it public and be really careful not to fall into the trap of saying: ‘We just can’t say anything because there’s no criminal case.’

“There’s a fair amount of information that could be made public, for the most part, and I think I’m detecting that the police are trying to do that. They realized that just saying ‘there are accusations, we can’t say anything more’ will not work these days.”