While Japan's government began the week noisily making big demands about trade and investment deals with the UK and European Union in light of Brexit, SoftBank was quietly tying the knot with British smartphone chip designer ARM.

On Monday, the two companies said that the £24 billion ($32 billion) takeover deal—which was struck in mid-July, just weeks after Britain voted for Brexit—had been completed.

ARM added that its chairman, Stuart Chambers, had quit immediately following the merger, alongside a number of resignations from non-exec directors. The chip designer said it was also in the process of severing ARM from listings on the London Stock Exchange and Nasdaq, as well as killing registration with the US Securities and Exchange Commission now that it's part of SoftBank.

Japanese telecoms giant SoftBank vowed in July that ARM would retain its senior management team, brand, and lucrative partnership-based business strategy. It added that the company would continue to be headquartered in Cambridge, England following the multi-billion-pound buyout of one of Britain's recent business success stories.

SoftBank also promised to double the staff headcount in the UK over the next five years. At present, ARM has more than 4,000 employees on its books worldwide.

However, the Japanese government warned in a 15-page memo—published to coincide with world leaders, including UK Prime Minister Theresa May, meeting at the G20 summit in China over the next few days—that, among other things, Britain should act "in a responsible manner to minimise any harmful effects to businesses that have heavily invested in the UK."

SoftBank's takeover of ARM is certainly a high-profile example. It's worth noting, too, that Japan already considers Britain to be a fading star by saying that the UK "was seen to be a gateway to Europe."

Among Japan's more striking demands—for ARM, at least—was for the UK and EU to ensure the "unified protection of intellectual property rights."