I can't really comment on the wisdom of Britain's decision to lower the language requirements for foreign nationals going there to work. I'm not British and have never lived there, and neither my taxes nor my livelihood are really threatened by the decision. I suspect that they will regret it, but it's not my problem.
I do think that if the information shown here is accurate, the Japanese government is doing its citizens and companies a disservice in the long run.
They have, through their embassy, apparently persuaded (pressured?) the British to exempt people going to Britain as ICTs (intra-corporate transfers) from the English language requirement if they are going to Britain for under three years, and to reduce the language ability required for skilled worker visas--including ICTs--for over three years, from being able to ‘‘understand the main ideas of a complex text on both concrete and abstract topics" and ‘‘interact with a degree of fluency and spontaneity that makes regular interaction with native speakers quite possible without strain for either party’’, to ‘‘ability to understand and use familiar everyday expressions and very basic phrases, to introduce themselves and others and ask and answer questions about basic personal details’’.
So the Japanese sarariman who's sent to work in London, instead of being able to discuss, say, the stock market, OPEC policies, global warming, terrorism, or even football, will now only need the typical result of six years of Japanese English education: "This is a pen", "I'm fine, thank you, how are you?", "Can you use chopsticks?", "Are you married?", and so on.
To be fair, "other missions" are mentioned in the article, so it's apparently not only the Japanese Embassy that was lobbying for reduced standards. I live here, though, and pay taxes here, and meet many people who are going to be sent abroad to work. Many of them could use much more preparation if they are expected to do a creditable job overseas.
It would be much better for the Japanese government to be spending time and money on raising the quality of their citizens' English than to be lobbying for foreign countries' working visa language requirements to be lowered.