Watching David Cameron’s government grappling with the Israeli boycott movement reminds me of one of the brighter moments in British public life during the turbulent Thatcher years. It came when Mrs T tried to stop the Olympic squad going to the 1980 Moscow Games in protest against the recent Russian invasion of Afghanistan. The Olympic movement, including Seb (now Lord) Coe and Steve Ovett, who would both win gold medals, said no. To her credit, Thatcher did not prevent them. In this instance, Cameron is not doing as well.

Here’s the Guardian’ s account of what happened in 1980, culled years later from the Whitehall archives, complete with pressure on Coe’s truculent father and manager, Peter. It was applied by a young ministerial thruster called Douglas Hurd.

There are many layers of irony in this story which hindsight lays bare. Led by the then US president Jimmy Carter, 62 countries stayed away and 81 went. The Russians retaliated by boycotting the Los Angeles games in 1984, the US armed what became Islamist militants who eventually drove the Russians out of Afghanistan, then sucked the Americans in, and us too. We still live with the consequences.

The Olympic movement has also since lost its halo. Coe’s is a bit tarnished. Isn’t life complicated?

What I remember with satisfaction was that the US Olympic committee buckled to political pressure, but ours didn’t. It’s not about the rights and wrongs of any particular boycott, it’s about the exercise of legitimate freedoms, which we are all supposed to be defending.

Just so with the Cabinet Office guidance, trailed since October but due out on Wednesday to coincide with minister Matt Hancock’s visit to Israel, that will punish local councils, NHS trusts and universities (all publicly funded) for imposing local boycotts on the goods from countries of which they disapprove.

It’s not just about Israel, but in the context of the decade-old international Boycott, Divestment and Sanctions (BDS) movement it’s mostly about Israel. The line is that Israel is the new apartheid South Africa and deserves to be treated as severely as the latter was before Nelson Mandela and sanctions forced the old regime to blink.

Personally, I’m not convinced by that analogy and find it distasteful. I’m not an expert, however, and plenty of people I respect who know more than I do think BDS policy and more is justified by the enduring plight of the Palestinians. But I’m told that an African National Congress delegation to the occupied West Bank was uneasily divided over the comparison with their own history.

Let’s park that debate for a moment with a passing nod to the energetic efforts of the Israeli government to discredit the BDS crowd, whose ambiguity on Israel’s right to exist troubles some close observers. I think the government has that right, regardless of the obnoxious folly of Binyamin Netanyahu’s government, which embarrasses many British Jews.

The primary issue here is whether Cameron and his Cabinet Office bagmen should threaten elected local authorities and other public bodies that decide to take a foreign policy stand. There is a long history of this sort of action, not just on apartheid.

The sight and sound of leftwing Lambeth council and others grandly declaring themselves “nuclear-free zones” was one of many such acts of anti-Thatcher gesture politics in the 80s. As noted above, she wasn’t above her own “Olympic-free zone” gestures either.

But she did ban councils from boycotting apartheid goods. She also banned the likes of Gerry Adams, now Sinn Féin’s top tweeter, from appearing on telly, though the actors required to speak his words made him sound much nicer.

It was all faintly ludicrous. In those days, Russian smart missiles weren’t actually smart enough to annihilate Southwark while sparing Lambeth next door. But being ludicrous should never be a sanctionable offence. In any case, assorted sanctions did the trick in South Africa, not Lambeth’s grapes ban perhaps, but sporting and investment (etc) boycotts, especially from the US Congress (not so brave on Israeli transgressions). Mandela emerged into freedom and eventual power.

The awkward fact is that some of us resist bans and boycotts while others are keen to embrace them for their perceived enemies. Those keenest to boycott the old USSR in the cold war decades were usually those keenest to protect the apartheid regime in South Africa on the spurious grounds that they were “on our side” against communism. Mrs T was of that school, and against Mandela’s “terrorists”.

But principles are not a pick-and-mix arena. A government that talks a lot about liberty is wrong to curtail the liberties of councillors in yet another sphere of activity. It’s insult piled on injury when this government cuts its grants while imposing new duties on them all the time. Shame on you, Dave. You sometimes make Tony Bair look like a deep thinker.

Leah (left), a Jewish worker, and Nida, a Palestinian, at the SodaStream factory in Mishor Adumim, West Bank. The company shut the factory last year after international protests. Photograph: Sipa/Rex/Heidi Levine

Still not convinced? It’s actually worse than that. Ministers hide behind the World Trade Organisation’s rules on procurement in its efforts to curry favour with Netanyahu. Though routinely accused of being anti-semitic by the headbangers, I’m not much of an Israel-basher (just look at some of the neighbours, eh!) and think Jeremy Corbyn gets it wrong on this, as on so much else. But even I wonder if fundraising closer to home, say north London, may be part of Cameron’s calculation on the low-minded side of the scales.

The awkward fact is that the Foreign Office has guidance as well as the Cabinet Office. Its guidance to firms is to steer clear of Israeli goods produced in the occupied West Bank. That’s in line with the European commission’s ruling in November that goods from the settlements should be labelled as such. After all, most international bodies and states (Britain included) regard the settlements as illegal. So it’s pretty cheeky for Cabinet Office ministers like young Hancock to threaten councils for being snooty about illegal goods and their suppliers. G4S, SodaStream and JCB are all in the campaigners’ sights.

And that’s the final rub. What do the campaigners and the government actually mean? There is a difference, surely, between Israeli goods we might choose to buy or not buy, as citizens or councils, and West Bank goods produced by farmers and others on those reckless settlements? Palestinians on the West Bank don’t export much, alas.

I’d say that West Bank goods are a fair target for a spot of opprobrium while not extending that target to Israel proper. That also goes for academic boycotts, where too many people are priggishly eager to engage in moral cherry picking. Intolerance in the name of diversity or victimhood should be seen for what it is.

But, despite reporters’ inquiries, the government has not yet made clear what precisely it means with its ban on bans. Labour is in a muddle too. As are most media reports. It all adds to the shabby air of improvisation that hangs over the issue. Clarity, please, minister.