It comes after the two Conservative leadership candidates raised questions about the new allegations.

Robert Jenrick suggested the information was being “hidden” from the public.

“We were told for months that this was not a terror-related incident and yet we learned that this individual, the suspect, had allegedly read al-Qaeda textbooks and had access to dangerous substances such as ricin,” he said .

“Given the extent of the public interest, I think it’s an important question to ask, why wasn’t this information brought into the public domain sooner? So I ask the public authorities and the Prime Minister, what they knew, when they learned it and why the decision was made not to be more honest and transparent with the public”.

Meanwhile, Kemi Badenoch suggested there were “serious questions that need to be asked of the police, the CPS and also about Keir Starmer’s response”.

She did not explain what those questions were, suggesting they should be asked in Parliament.

Police say it is “definitely not the case” that they kept the items from the public. It would be highly unusual for them to reveal details of a live police investigation.

The CPS suggests it took time to bring the charges because this was a “long and complex investigation”.