Why is this significant for Donald Trump?

The new information reveals that the Moscow project was being pursued with Russian officials while Mr Trump was forging ahead in the race to become Republican presidential candidate.

At the same time he was repeatedly complimenting the Russian president, describing President Putin as "brilliant" (January 2016) a "strong leader" (March 2016) and saying that "we're going to have a great relationship with Putin and Russia" (April 2016).

The conflict of interest is obvious. Mr Trump stood to make millions of dollars in profit if the deal went through and his team were actively involved in negotiations with officials close to the Russian president to make it happen. Meanwhile Russia was involved in efforts to influence the presidential election in Mr Trump's favour, according to the US intelligence community.

Cohen's admissions will also force a reassessment of earlier reports and conclusions about the links between Russia and the Trump campaign. One example is Mr Peskov's version of events: in his initial statement in August 2017 he said that his office did not reply to Cohen's email but on Thursday he admitted that they did call Mr Cohen back to explain "that we have nothing to do with construction issues in the City of Moscow".

The conclusion of the House report that there was no evidence of collusion was also partly based on Cohen's lie to Congress that no government officials were involved in the Moscow project.

It would seem unlikely that the president was unaware that Cohen had lied to Congress. As former prosecutor Ken White said: “The conclusion that the President of the United States knew that his personal counsel was repeatedly lying to the Congress of the United States about the President’s business is inescapable under these circumstances.”