brent: dw's barbara wesel at number 10 downing street in london. barbara, thank you.cross the atlantic, it has been a contentious day on capitol hill in washington dc. former special counsel robert mueller has been testifying before a congressional committee about his probe into russian interference in the 2016 election, and whether the trump campaign colluded with moscow. he told lawmakers the investigation found inadequate evidence to prove that there was a conspiracy, but he said once again, his investigation did not clear president trump of obstructing justice. many are viewing mueller's testimony today as a last chance for democrats to build a case for impeaching the president. >> mr. mueller, are you looking forward to this? reporter: robert mueller, who spent two years leading an investigation determining if president trump had colluded with russia, did not look like he wanted to be there. but for democrats and republicans in congress, this was an opportunity to get their points across live on tv. >> the report did not conclude that he did not commit obstructio