Boris Johnson has arrived in New York for talks with senior members of Donald Trump's transition team, the Foreign Office said.

News of the Foreign Secretary's surprise trip emerged just hours after Theresa May labelled the US President-elect's controversial comments about groping women "unacceptable".

Mr Johnson was expected to meet Mr Trump's son-in-law Jared Kushner and the president-elect's strategist Steve Bannon in New York.

A spokesman said: "Following the successful meeting last month between the Prime Minister's chiefs of staff and President-elect Donald Trump's team, Foreign Secretary Boris Johnson is undertaking a short visit to the US for meetings with close advisers to the president-elect and senior Congressional leaders.

"The discussions will be focused on UK-US relations and other foreign policy matters."

The Government has been seeking to forge links with the incoming Trump administration, and Mr Johnson's visit follows meetings between the president-elect's team and Ms May's closest advisers Nick Timothy and Fiona Hill.

Mr Trump has said he is "very much" looking forward to meeting Ms May in the coming months and described Britain as a "very special" ally in a message on Twitter.

But Ms May was challenged about the controversial tycoon's previous comments during her first television interview of the year.

Mr Trump's presidential campaign was plunged into crisis after a 2005 tape recording came to light of him bragging to TV host Billy Bush about groping women and that he can "grab them by the pussy" because of his celebrity status.

Ms May was asked how the comments made her feel as a woman on the Sophy Ridge On Sunday show on Sky News.

"I think that's unacceptable, but in fact Donald Trump himself has said that and has apologised for it," Ms May said.

"But the relationship that the UK has with the United States is about something much bigger than just the relationship between the two individuals as president and prime minister.

"That's important, but actually we have a long-standing special relationship with the United States.

"It's based on shared values and it is a relationship where, actually in the UK, we feel we can say to the US if we disagree with something that they are doing."

The Prime Minister and Mr Trump are due to meet in Washington in the spring following the preparatory meetings by her aides over the Christmas period.

A date for the meeting is yet to be revealed, but it is expected to come within weeks of Mr Trump's inauguration on January 20.

The status of the special relationship between the two long-time allies has faced fierce speculation ever since Mr Trump won the US presidential election.

Theresa May calls Donald Trump's comments 'unacceptable'

That speculation has been partly fuelled by the president-elect's apparent close relationship with the former Ukip leader Nigel Farage.

But Ms May insisted she envisages a bright future for the countries.

"From the conversations I have already had - I have had two very good, positive conversations with Donald Trump already - I think we are going to look to build on that relationship for the benefit of both the US and the UK," she said.

"I think that is something that is optimistic and positive for the UK for the future."

Mr Trump's election and his praise for Russian president Vladimir Putin has also cast doubt on the future of Nato, in particular whether the US will continue to uphold a commitment to come to the aid of allies if they are invaded.

But Mrs May suggested the US remains committed to the military alliance.

She said: "The Article Five of Nato says that we do go to the support of any Nato country that has military action against it."

She added: "Sometimes people think that there is going to be a change in the American approach to Nato. From the conversations I have had, I think America remains fully committed to Nato as we do.

"We are already taking some steps to show the seriousness with which Nato considers its responsibilities. There will be UK troops on exercise in Estonia this year."