Ministers and senior officials at every level of government are holding talks with US counterparts this weekend in a last-ditch effort to secure a carve-out from swingeing import taxes.

Government sources said ministers were raising Donald Trump’s looming tariffs as the “No 1” issue in every conversation with the US.

Trump announced on Wednesday that he would introduce a 25% tariff on car imports to the US on 3 April, which would hit British carmakers such as Bentley and Aston Martin.

The government is seeking an exemption to the car tariffs and the wider package of measures that Trump is drawing up for next week as part of its plan for a US-UK “economic prosperity deal”.

Officials told the Guardian this week they were confident that there was an appetite for a deal on the US side, but less confident that an agreement could be reached before further levies come in on 2 April, which Trump has branded “liberation day”.

The UK is one of four countries, alongside Australia, Japan and South Korea, that are engaged in intensive negotiations to secure exemptions before the deadline, according to a government source.

Jonathan Reynolds, the business and trade secretary, told a Chatham House event on Thursday that ministers were “continuing an incredibly intensive set of negotiations and we’ll know pretty soon what the outcome of that will be”.

But he conceded that a deal might not be done by 2 April, saying: “Our view would have been we would not have wanted any tariffs applied to the UK while we’re having this conversation, but we’re pretty close to what the US calls ‘world tariffs day’ next week,” he said.

In their conversations with their US counterparts, officials and ministers are hammering home the point that the trading relationship between the US and UK is balanced. Trump has repeatedly railed against the US’s trade deficit with leading powers such as China and the EU.

The US is the single largest individual-country trading partner for the UK, in a relationship worth almost £300bn a year. In 2023, the UK imported £57.9bn of goods from the US, and exported £60.4bn the other way – including car exports worth £6.4bn, almost 20% of the country’s total international sales.

Downing Street officials are closely involved in the talks, including the prime minister’s “sherpa” Michael Ellam and his business adviser Varun Chandra. The latter accompanied Reynolds on his trip to Washington DC to discuss the economic prosperity deal earlier this month.

On that visit Reynolds met Howard Lutnick, the US commerce secretary, Jamieson Greer, the US trade representative, and Mark Burnett, Trump’s special envoy to the UK. Some officials stayed behind in Washington to keep talking through details. Staff at the UK embassy in Washington, led by Peter Mandelson who is a former EU trade commissioner, are also closely involved.

While it is concentrated on securing a deal, the government has not ruled out retaliatory tariffs. Keir Starmer said on Friday that the UK “reserves the right to respond” to US tariffs next week “our national interest has to come first”.

During a visit to Yorkshire, he said: “Obviously, any tariffs are concerning and we’re working hard with the industries and sectors likely to be impacted. None of them want to see a trade war, which is why we’re engaged in discussions with the US about mitigating the impact of tariffs.” The US is the second largest export market for cars built in the UK, after the EU.

Some question whether the UK’s approach is the right one. David Henig, a trade expert, said amounted to “a gamble if you’re not one of the countries that’s most targeted – which we’re almost certainly not – that it’s still better to seek out a deal than, frankly, keep your head down and be ignored”.

The concern is that the government is offering up big concessions to the US unnecessarily, when Trump’s package of tariffs is set to be narrower than feared and the UK was never a target for them in the first place. Ministers have offered up the £800m digital services tax, which targets US tech companies, as part of the talks for an economic deal. “You start to wonder is this going to be a good deal? It might all pay off in the end but it’s looking like a gamble,” Henig said.

Britain’s trade dealings with the US have previously involved roadblocks over allowing US farmers to sell chlorinated chicken and hormone-fed beef to UK consumers, and there are signs that those difficult sanitary and phytosanitary (SPS) issues are coming up again.

Reynolds told the Chatham House event: “There are some difficult areas for us. We have a manifesto commitment to maintaining our SPS regime. That is something we very much committed to, that is not always something other countries see eye to eye to us on.”

William Bain, the head of trade policy at the British Chambers of Commerce, said: “There will be frantic discussions from all countries with the US administration over the weekend to get to best place they can ahead of the announcements. If anyone has a chance of exemptions, it is the UK. We always felt it was going to come US before 2 April and a fair chance it might go beyond the wire as well.”