- Video report by ITV News political correspondent Carl Dinnen
Boris Johnson and his Russian counterpart have clashed over Crimea and alleged Russian cyber attacks on the West, arguing publicly during the first visit of a UK foreign secretary to Moscow in over five years.
In an extraordinarily blunt exchange during a joint press conference Mr Johnson even appeared to accuse Moscow of attempting to interfere in the Brexit referendum, claims Russia denies.
When Mr Lavrov told the assembled journalists that Mr Johnson had confirmed Russia had not interfered in the referendum, Mr Johnson interrupted to add: "Not successfully."
Mr Lavrov said Mr Johnson was making up accusations of Russian interference in other countries' democratic processes "out of thin air", and called the Foreign Secretary a "hostage" to untrue Western narratives on the issue.
But Mr Johnson insisted there was "abundant evidence" of Russian interference in polls in the US, Germany, Denmark and France.
Ahead of his trip, the foreign secretary had said that relations between the UK and Russia "haven't been so bad for a very long time".
During the meeting Mr Lavrov acknowledged as much, saying "it's no secret relations are not good" and added: "You prefer to talk about our differences publicly, we prefer to do it face to face."
ITV News political correspondent Carl Dinnen, who was present at the press conference, said the two diplomats were "openly sparing ... the hostility was ill-concealed".
- ITV News political correspondent Carl Dinnen reporting from Moscow:
In an exclusive interview with ITV News after the conference, however, Mr Johnson played down the exchange, saying: "There are difficulties, we can't shy away from those, but there are also important things that we have to discuss where we can make progress together."
Pressed on whether he was accusing Russia of interfering in the Brexit referendum, Mr Johnson told ITV News: "I don't have any evidence that Russia is being notably successful - if it is doing this - I don't have any evidence it is being notably successful in the UK."
But he again said there was evidence Russia had attempted to "manipulate the electoral process in some other countries".
Mr Johnson's comments on Russian cyber campaigns aimed at influencing events in the West are the latest in a string of such accusations.
Last week Theresa May accused Russian President Vladimir Putin of using cyber-espionage to sow discord in the West, warning Moscow: "We know what you are doing. And you will not succeed."
Meanwhile, GCHQ on Wednesday revealed that Britain was developing a "full spectrum" of cyber weaponry.
Also on his trip, in a move likely to further antagonise his Russian hosts, Mr Johnson laid a bunch of red roses at the spot on Bolshoy Moskvoretsky Bridge where opposition leader Boris Nemtsov was assassinated in 2015.
Mr Nemtsov was deputy prime minister of Russia under Boris Yeltsin and a declared admirer of Margaret Thatcher who tried to institute reforms to push Russia towards democracy and free markets.
Mr Johnson added his flowers to a pile of tributes from Nemtsov supporters, which are left on the bridge on a daily basis, but cleared away every night.
Earlier, the Foreign Secretary also laid a wreath at the Tomb of the Unknown Soldier at the Kremlin and made a tour of Red Square.
Mr Johnson also addressed university students and in an apparent criticism of Mr Putin's record on press freedom, told them that "a society where journalists are shot because they investigate the business doings of the rich and powerful" was likely to be less prosperous.
"The more tolerant a society is, the more supportive of free speech it is, the more likely that society is to be rich and successful," the Foreign Secretary said.