The German equivalent of CID warned in a confidential memo to regional authorities last March, that it has intercepted communications indicating Amri was planning a suicide attack, and recommended he be deported.

But the state government of North Rhine-Westphalia ruled that an order to expel him was not legally enforcable.

The new disclosures will add to questions over why Amri was allowed to remain in Germany and move freely around the country even though he was known to be a threat.

They come after Uwe Jacob, head of the North Rhine-Westphalia Landeskriminalamt, the regional CID, admitted him and his staff suspected Amri was behind the Berlin attack the moment they heard of it.

“Our immediate reaction was please don’t let it be Amri,” Mr Jacob told a parliamentary inquiry on Friday.