Theresa May says she “won’t be afraid” to tell Donald Trump if he says or does anything she feels is “unacceptable”.
The two will hold talks in the White House on Friday on issues such as trade and security, with the prime minister being the first foreign leader to meet the US President since he took office.
She told the BBC that the special relationship between the two countries enabled her to raise difficult matters.
She insisted she had a “strong track record” of defending women’s rights.
Thousands of protesters took part in demonstrations on both sides of the Atlantic on Saturday as part of an international campaign to highlight concerns over the president’s views on gender and racial equality.
Mrs May told Andrew Marr she was looking forward to meeting Mr Trump for the first time in Washington and to build on the strong relations of past UK and US leaders.
Asked whether she would raise some of the comments that Mr Trump made about women and women’s issues during the presidential campaign, she said.
“I have already said that some of the comments Donald Trump has made in relation to women were unacceptable. Some of those he himself has apologised for.
Mrs May said she would be making a “big statement about the role of women” by meeting and negotiating with the US President on an equal footing.
Citing her work on introducing new laws on modern slavery and domestic violence, she said she had a record of defending women’s interests while in power.
“I will be talking to Donald Trump about the issues we share and how we can build on the special relationship,” she said.
“It is the special relationship that allows us to say when something is unacceptable.
“Whenever there is something I find unacceptable, I won’t be afraid to say that to Donald Trump. ”
Asked what she thought about Mr Trump’s inauguration speech, she said his vow to put America first was a “clear message” but all leaders prioritised their own nations’ interests.
She said she was not overly alarmed by Mr Trump’s protectionist rhetoric on trade, saying the US President hade made it clear he wants a strong relationship with the UK and she expected to be able to raise the matter while in Washington.
“He and people around him have also spoken about the importance of a trade agreement with the UK and that is something that are looking to talk to us about an early stage. ”
Whether she was a strong believer in free trade as a lynchpin of growing prosperity, she also recognised the economic benefits of globalisation must be spread more widely.
She said the US and UK had a deep and broad-based relationship, spanning a range of shared interests and values.
She added: “There are issue that we will work on together in the future – the importance of Nato and defeating terrorism.
“These are issues where we share the challenges and see the threats, where we have worked together in the past and will do so by the future. “