According to https://en.wikipedia.org/wiki/International_Computers_Limited
International Computers Limited (ICL) was a British computer hardware, computer software and computer services company that operated from 1968 until 2002.
Okay, straightforward and unsurprising enough so far.
As of 1971, the United Kingdom was unusual in Europe for IBM not having more than 50% of the computer market,
This is mildly surprising, and I'm curious about why.
although an observer stated that the company constrained the size of its British subsidiary to keep ICL alive.
Now this is where it gets really surprising. Why would IBM do that?
Deliberately keeping a competitor alive to fend off antitrust scrutiny is not necessarily unheard of. (It has been conjectured that this was one reason Microsoft invested in Apple in the nineties.) However, while IBM did indeed have antitrust trouble, that was with the US government. So if that was the reason, wouldn't it want to keep a US rather than UK competitor?
Was there some aspect of UK politics at the time, that led IBM to expect some backlash if it became a monopoly in that country? Or was there some other reason for the claimed behavior?