But ARM's chief executive played down the threat of export bans. It isn't to do with the ownership of the company, it's all to do with analysis of the product itself, Simon Segars told the BBC. The majority of our products are designed in the UK or outside the US, and the majority of our products don't fall under much of the US export control set of rules. Mr Huang added that ARM had some of the finest computer scientists in the world in Cambridge and he intended to both retain them and attract others to what would become Nvidia's largest site in Europe. The UK prime minister's spokesman said ministers have spoken to both companies, adding that the government would be scrutinising the deal including what it means for the Cambridge HQ. ARM creates computer chip designs that others then customise to their own ends. It also develops instruction sets, which define how software controls processors.

It is based in Cambridge but also has offices across the world, including a joint venture in Shenzhen, China. Hundreds of companies license its innovations including Apple, Samsung, Huawei and Qualcomm. To date, ARM says 180 billion chips have been made based on its solutions. When Softbank acquired ARM, it promised to keep the company's headquarters in the UK and to increase the number of local jobs, which it did. Softbank's founder Masayoshi Son described the firm as being a crystal ball that would help him predict where tech was heading. But losses on other investments, including the office rental company WeWork, prompted a rethink. California-headquartered Nvidia overtook Intel to become the world's most valuable chipmaker in July. Until now, it has specialised in high-end graphics processing units (GPUs). These are commonly used by gamers to deliver more detailed visuals, as well as by professionals for tasks including scientific research, machine learning, and cryptocurrency mining. Nvidia is also one of ARM's clients, using its designs to create its line-up of Tegra central processing units (CPUs). Under the terms of the deal, Nvidia will pay Softbank %3C/a""> ">

It will follow with up to a further $5bn in cash or stock if certain targets are met. Nvidia will also issue $1.5bn in equity to ARM's employees. But experts say one risk Nvidia faces is that the takeover could encourage ARM's wider client list to shift focus to a rival type of chip technology, which lags behind in terms of adoption but has the benefit of not being controlled by one company. ARM is facing growing competition from RISC-V, an open-source architecture, wrote CCS Insight's Geoff Blaber in a recent research note. If its partners believed that ARM's integrity and independence was compromised, it would accelerate the growth of RISC-V and in the process devalue ARM. Mr Blaber also suggested regulators might block the deal. This process will take months if not years with a high chance of failure, he told the BBC. Mr Huang has said that he expects it to take more than a year to educate regulators and answer all their questions, but said he had every confidence they would ultimately approve Softbank made commitments to secure jobs and keep ARM's headquarters in the UK until September next year.