The impeachment inquiry into Donald Trump has moved at such pace and revealed so much that it is strange to think that it only started a month ago.

In that time a classified transcript of the president’s call to another world leader has been made public, along with private texts from alarmed US diplomats and the full complaint from the central whistle-blower.

Behind closed doors much more has taken place that we don't know about, with the three congressional committees leading the probe hearing more than 40 hours of witness testimony.

Every president in such circumstances – and there have only been three others in US history – would seek to shape and influence the proceedings, even though the process is out of their total control.

Mr Trump is no different. But those attempts to curb the political damage have not been particularly successful. There is a feeling that the inquiry is now running away from him. Here is why.

1. Trump’s ‘no engagement’ order is being ignored by government officials

A fortnight ago, one of the White House’s top lawyers, counsel Pat Cipollone, sent the impeachment inquiry an eight-page letter that could be summarised in two words: get lost.

The letter spelled out in detail the US government's argument that the investigation was “baseless”, saying that it lacked “any legitimate constitutional foundation” or “pretense of fairness”.