Boris Johnson has claimed Britain is “first in line” for a post-Brexit trade deal with the US, following meetings with Republican congressional leaders including Mitch McConnell and Paul Ryan.

The foreign secretary visited New York and Washington, paving the way for an official trip by Theresa May to meet Donald Trump later this year. For Mr Johnson, the visit was also an opportunity to build bridges after he criticised Mr Trump during the presidential election campaign.

Having joked in December 2015 he wouldn’t visit New York because of the “real risk of meeting Donald Trump”, he praised the president-elect’s “very exciting agenda of change”. He added: “One thing that won’t change, though, is the closeness of the relationship between the US and the UK . . . We hear that we are first in line to do a great free-trade deal with the United States. So it’s going to be a very exciting year for both our countries.”

His words were echoed by Bob Corker, the chair of the Senate foreign relations committee, who told the BBC that it would be “our priority to make sure that we deal with [the UK] on a trade agreement”.

The comments mark a clear break with Barack Obama’s claim, during the EU referendum campaign, that Britain would be “at the back of the queue” in trade negotiations if it voted to leave. Brexiters criticised Mr Obama’s intervention in British politics, while claiming it actually antagonised swing voters.

“The special relationship between the United States and United Kingdom is strong, and we are determined to make it even stronger,” Mr Ryan, speaker of the House of Representatives, said after meeting Mr Johnson. “In this spirit, Secretary Johnson and I discussed several areas of mutual concern for our nations, including reaffirming our commitment to NATO and exploring opportunities for improving bilateral trade relations.”

Despite the apparent goodwill on trade, there remain potential differences between the US and UK governments on issues including how to deal with Vladimir Putin and climate change.

Mrs May is due to visit the US in the coming months, having already tried to see off an attempt by former UK Independence party leader Nigel Farage to act as a go-between with Mr Trump. Mr Farage, once reported to be planning to move to the US, has begun a daily radio talk show in London.

Mr Johnson’s trip was intended to be low-key: one official said it was only announced publicly when he was spotted at the airport.