Britain on Monday detailed its red lines in imminent negotiations with the US over a free trade deal, vowing to safeguard its health service, food safety and animal welfare.

The British government, which can now strike trade agreements around the world after leaving the EU on January 31, said it wants an “ambitious and comprehensive” accord with its transatlantic ally.

London said it wants to increase US market access for its businesses and investors, while lowering prices on goods and services for British producers and consumers.

But it pledged to “rigorously protect” public services in any deal, following fears its National Health Service (NHS) could be opened up to American companies leading to higher healthcare and medicine prices.

“The NHS is not for sale,” the Department for International Trade said in a statement ahead of the publication of the negotiation objectives.

It also promised to uphold “high domestic standards” on food safety and animal welfare, amid concern in Britain they could be harmed in a transatlantic deal.

“We’re going to drive a hard bargain to boost British industry,” Prime Minister Boris Johnson said.

“Trading Scottish smoked salmon for Stetson hats, we will deliver lower prices and more choice for our shoppers.”

His government said it would also unveil an analysis showing that the British economy will get a £3.4 billion ($4.4 billion) boost from a US-UK free trade deal.

Britain exports more to the US than any other country, but that is dwarfed by its trade with the now 27-member European Union, which accounts for almost half of all UK exports – nearly three times the level of the US.

London began negotiations with Brussels on Monday on a trade deal with the bloc, which it hopes to conclude by the end of the year.

The two sides have already agreed to a post-Brexit standstill transition until December 31, with the current rules remaining in place, while they work out the new economic and security partnership to replace 47 years of integration.

Britain’s talks with the US, which it expects to begin later this month, will be headed by Crawford Falconer, formerly New Zealand’s trade ambassador.

Wendy Cutler, a former US trade negotiator, told BBC Radio over the weekend that “success can be achieved” if “negotiators can find creative ways to get around complex and competing demands”.

“The UK negotiators are going to need to be very prudent and make sure that they don’t inadvertently agree to something that’s going to anger the EU or the US,” she added.

Meanwhile Britain has said it will also publish its objectives for talks with Australia, Japan and New Zealand shortly, with the aim of having 80 percent of its external trade covered by deals by 2022.