When Masayoshi Son, the billionaire founder and chief executive of Japan’s Softbank, announced he was buying U.K. computer chip design firm Arm for $32 billion in 2016, the British government was quick to praise the deal as evidence that the country remained an attractive place for foreign investment even though its population had just voted a month earlier to leave the European Union.

But now, four years later, Softbank is selling Arm to U.S. chip giant Nvidia for $40 billion and the U.K. government may not take such a sanguine view of the new ownership arrangements.

When Softbank purchased Arm, the British government forced the Japanese company to commit to a legally-binding set of conditions: these included keeping Arm based in Cambridge, where the company was already in the process of constructing a new signature headquarters building, and critically, doubling Arm’s U.K. headcount to 3,500 employees within five years.

The company, which now employs close to 3,000 people in the U.K., remains shy of that goal. And this time, Jensen Huang, Nvidia’s chief executive, has scrupulously avoided making a firm numerical commitment to further hiring.

“We want more great engineers not fewer,” he said on Monday, without mentioning how many more engineers his company may hire.

Instead, Huang offered vaguer assurances that Nvidia will invest in an artificial intelligence research center in Cambridge, including building one of the world’s most powerful supercomputers there.

“We are open-minded to talk to the U.K. government on a partnership that enables us to invest in the U.K. and expand the R&D presence of Arm,” he said.

Some analysts were skeptical of Jensen’s assurances. “This remains to be seen,” Gartner analyst Alan Priestley said. “Nvidia already has a major investment in its U.S.-based locations for A.I. research.”

One of Arm’s original co-founders, the venture capitalist Hermann Hauser, said he was dismayed at Arm’s sale. “I think it’s an absolute disaster for Cambridge, the U.K., and Europe,” Hauser told the BBC’s Radio 4 on Monday morning.

Hauser said he worried Nvidia, which is based in Santa Clara, Calif., will ultimately shift Arm’s headquarters to the U.S. More importantly, he said Nvidia would destroy’s Arms business model, which has depended on its independence —the company licenses its designs to many chipmakers and as well as companies that incorporate their own chip designs into products, such as Apple and Samsung. All these companies compete with one another. Now Arm is being acquired by one of those competitors, which may use its position to hike licensing and royalty fees on its rivals or to deny them access to the latest technology. Huang said Nvidia valued Arm’s independence and business model.

Hauser also said he worried about Nvidia’s acquisition by a U.S. company amid growing conflict between Washington and Beijing over access to next generation technology. He said Nvidia’s purchase would make it easier for the U.S. government to use its export control regime to prevent Arm from licensing its semiconductor designs to Chinese companies.

“If hundreds of U.K. companies that incorporate Arm’s [chip designs] in their products want to sell it or export it to anywhere in the world, including China, which is a major market, this decision on whether they’re allowed to export it will be made in the White House and not in Downing Street,” he said. “I think this is terrible.” 

Simon Segars, Arm’s CEO, said U.S. export restrictions were based on where a technology was designed and licensed, not the nationality of its ownership. He said “the majority” of Arm’s technology was “designed in the U.K. or outside the U.S. and mostly don’t fell under U.S. export controls.” Huang also said Nvidia’s purchase would not change the legal jurisdiction of Arm’s technology.

Hauser has written an open letter to U.K. Prime Minister Boris Johnson asking him to block the deal unless Nvidia provides firm guarantees on the number of jobs in Cambridge, no preferential access to Arm’s technology for Nvidia and an exemption to U.S. export controls for British companies.

Hauser’s call has been joined by Prospect, a union that represents science and technology workers. The opposition Labour Party has also called for government scrutiny of Nvidia’s purchase. On Friday, as rumors of the impending deal swirled, Labour shadow business secretary Ed Miliband said that the government was wrongly “ignoring the potential consequences of this takeover, including the possible implications for where the company is headquartered and the thousands of jobs in Britain that depend on it.”

Oliver Dowden, the U.K.’s culture secretary, is considering whether to ask the government’s Competition and Markets Authority to undertake a full review of the deal, The Guardian reported. Such reviews can take many months to complete and open up the possibility of the regulator blocking the deal, which it can do if believes the purchase would in any way undermine national security, financial stability or plurality in media ownership. When Softbank bought Arm in 2016 it avoided this kind of review, in part due its legally binding commitment on jobs.

Huang said that Nvidia had only just begun any discussions of the deal with the U.K. government and that there remained “plenty of time” before the deal would close to reach an agreement on potential commitments in terms of investment or jobs.

Beyond job losses, the sale of Arm to a U.S. tech giant is another blow to British prestige. The country has been proud of its technology sector, which has been a bright spot in an economy that has been battered by long-term secular decline in industries ranging from mining and steel to oil and gas to retail.

But, despite playing host to a number of promising startups, the country’s tech sector has been unable to grow businesses with the scale and global impact of those birthed in the U.S.

Arm, prior to Softbank’s acquisition, was one of the few independent British companies that was an undisputed world leader in a technological field. From Lovefilm, a DVD subscription and video streaming service that was bought by Amazon and incorporated into its Prime Video product, to artificial intelligence pioneer DeepMind, which was acquired by Google, many of the U.K.’s most promising young companies have wound up in the hands of deep-pocketed Silicon Valley tech giants.

Other mega tech deals involving British firms have ended badly. In 2011, Hewlett Packard bought Autonomy, an enterprise software company based in Cambridge that was a one-time darling of the British technology sector, for more than $11 billion, only to turn around and write off $8.8 billion of that purchase one year later after discovering what it claimed was widespread accounting fraud. The case has resulted in on-going civil and criminal litigation on both sides of the Atlantic.