Robert Mueller, the special counsel investigating links between Donald Trump's campaign and Russia, has detailed how the FBI missed a chance to question a London-based professor caught up in the inquiry.

Prosecutors working for Mr Mueller filed court documents recommending a jail sentence for George Papadopoulos, a former Trump campaign foreign policy adviser.

Mr Papadopoulos has admitted lying to the FBI about his contacts with Professor Joseph Mifsud.

The professor is alleged to have told Mr Papdopoulos that the Russians possessed "dirt" on Hillary Clinton in the form of emails, before those emails became public. Prof Mifsud, who is Maltese, has denied doing so.

The Mueller court documents said Mr Papadopoulos caused irreparable damage to the Russia investigation because he lied repeatedly to agents during a January 2017 interview.

Those lies, prosecutors said, resulted in the FBI missing an opportunity to properly question Prof Mifsud.