The wife of Downing Street adviser Dominic Cummings has denied she was the second woman allegedly groped by Boris Johnson at a 1999 lunch while he was editor of The Spectator.

Journalist Charlotte Edwardes has said that the prime minister squeezed her thigh and that of another unnamed woman without their permission at the magazine’s offices in London.

Asked if the allegations were true during a TV interview at the Conservative annual conference in Manchester, Mr Johnson responded simply: “No.”

And Mr Cummings’ wife, Spectator commissioning editor Mary Wakefield, moved to quash rumours whirling around the Manchester gathering that she might be the other woman mentioned.

In a statement, she said: “I am not the woman referred to in Charlotte Edwardes’ column.

“Boris was a good boss and nothing like this ever happened to me. Nor has Charlotte, who I like and admire, ever discussed the incident with me.”

Boris Johnson and Brexit merchandise for sale at the Tory conference Show all 10 1 /10 Boris Johnson and Brexit merchandise for sale at the Tory conference Boris Johnson and Brexit merchandise for sale at the Tory conference A Boris Johnson doll for sale at the Conservative Party Conference in Manchester on 29 September PA Boris Johnson and Brexit merchandise for sale at the Tory conference Mugs with Boris Johnson's portrait for sale at the Conservative Party Conference in Manchester on 29 September AP Boris Johnson and Brexit merchandise for sale at the Tory conference A Boris Johnson themed T-shirt for sale at the Conservative Party Conference in Manchester on 29 September AFP/Getty Boris Johnson and Brexit merchandise for sale at the Tory conference Boris Johnson and other Conservative themed cards for sale at the Conservative Party Conference in Manchester on 29 September AP Boris Johnson and Brexit merchandise for sale at the Tory conference Boris Johnson posters for sale at the Conservative Party Conference in Manchester on 29 September EPA Boris Johnson and Brexit merchandise for sale at the Tory conference Copies of The Conservative newspaper are ready to be distributed during the Conservative Party conference on 30 September Getty Boris Johnson and Brexit merchandise for sale at the Tory conference "GET BREXIT DONE" mugs alongside other Conservative merchandise at the party conference in Manchester on 29 September PA Boris Johnson and Brexit merchandise for sale at the Tory conference Assorted Conservative merchandise for sale at the party conference in Manchester on 29 September PA Boris Johnson and Brexit merchandise for sale at the Tory conference Books about Jacob Rees-Mogg and Jeremy Corbyn for sale at the Conservative Party conference in Manchester on 29 September Getty Boris Johnson and Brexit merchandise for sale at the Tory conference A variety of books for sale at the Conservative Party conference in Manchester on 29 September Getty

Allegations about Mr Johnson’s past behaviour towards women risked overshadowing the annual Conservative conference, where the prime minister is trying to foreground his message that the Tories will “get Brexit done” then move on to investment in domestic priorities such as health, schools and the police.

Downing Street was forced to issue a statement denying Ms Edwardes’ claims.

But the journalist stood by her claims, tweeting: “If the prime minister doesn’t recollect the incident then clearly I have a better memory than he does.”

Asked whether it was true he touched a woman’s thigh without her consent, Mr Johnson told Sky News: “No, and I think what the public want to hear is about what we are doing to level up and unite the country.”

Mr Johnson insisted that the row had “not at all” cast a cloud over the conference.

And he claimed that some allegations were politically motivated: “There are a lot of people who basically want to stop us delivering Brexit on 31 October but I have to tell you we are not going to be deterred from that ambition. We are going to get on and do it.”

Dominic Cummings’ wife was rumoured to be involved in the recent allegations against the prime minister (PA)

The prime minister insisted on Sunday that he had acted with “full propriety” in relation to US businesswoman Jennifer Arcuri, after claims emerged that she had said she was in an intimate relationship with him during his time as London mayor. He said that no conflict of interest arose when her company was awarded publicly funded grants by City Hall and given access to overseas business missions which he led.

Describing the Spectator lunch in her Sunday Times column, Ms Edwardes said: “I’m seated on Johnson’s right; on his left is a young woman I know.

“More wine is poured; more wine is drunk. Under the table I feel Johnson’s hand on my thigh. He gives it a squeeze.

“His hand is high up my leg and he has enough inner flesh beneath his fingers to make me sit suddenly upright.”

After the lunch, she said she had confided in the young woman who was sitting on the other side of Mr Johnson, who told her: “Oh God, he did exactly the same to me.”

Ms Edwardes did not name the woman allegedly involved.

Former cabinet minister Justine Greening said the allegations were “serious” and “damaging” and raise questions about the prime minister’s character.

Justine Greening on damaging allegations against Boris Jonnson

Ms Greening, who was stripped of the Conservative whip for rebelling over Brexit, said she had never personally witnessed any behaviour of the kind alleged from the prime minister, but said it was important that the claims were dealt with “appropriately” by Downing Street to maintain public faith in the integrity of politics.

“There are obviously deeply concerning allegations that have been made and I think they really do go to the heart of the character and integrity that people have a right to expect from politicians running this country,” she told Sky News.

“So I think that No 10 should deal with these allegations.

“They are serious and it’s important that people who seek to run Britain and lead this country are those that the electorate has faith in. I think it’s important for the electorate that they do set high standards for people in public life.”

Asked whether the allegations chimed with her own impression of Mr Johnson as an individual, the former minister said: “I’ve not seen that side of Boris. I can only talk about the person I’ve sat in cabinet with and worked with.