China’s new security law is as vague as it is alarming – indeed, that it is the second arises from it being the first – as well as a shameless breach of the Joint Declaration.  So we understand that the Government’s guarantee of a pathway to citizenship for about 3.5 million of Hong Kong’s citizens is designed not so much as a door as a lever.

Its main purpose is clearly to put counter-pressure on Beijing: to send a message that China will not be able with one hand to grip Hong Kong’s wealth, and with the other strangle its freedoms – at least, not without paying the penalty of losing some of those who create that prosperity in the first place.

In any event, a pathway is not a destination, and the details of Boris Johnson’s proposed scheme have not yet been set out.  And it is very unlikely that 350,000 Hong Kongers would all turn up at Britain’s airports in the same year, or indeed at all, if the plan comes to fruition.  Many would be likely to prefer other destinations, such as Taiwan.

That said, we are puzzled by the dog that isn’t barking in the night – with the exception of a recent growl on this site from Andrew Green of Migration Watch, who described the Government’s offer as an “extraordinarily ill-conceived policy that could cost it the next election”.

His point was that when all the qualifications about pathways, details and probabilities are stripped away, a fact remains: namely, that Boris Johnson is dangling an offer of British citizenship before three million people, complete with its implications for housing, healthcare, schools, roads, rail, welfare and so on.

Now it may be that public opinion on immigration has somehow shifted significantly post-Brexit.  Or that the long enthusiasm of some on the Right for opening up Britain to Hong Kongers, a passion that reaches back to the row over a citizenship extention in Margaret Thatcher’s time, has rubbed off on the population more widely.

Perhaps the prospect of a mass of hard-working, family-orientated new arrivals, transferring their talents to Britain and raising our tax receipts in the process, is welcome to the mass of hard-working, family-orientated Red Wallers who leant the Prime Minister their votes last December.

It certainly appears not to bother part of the elites – namely, our own survey panel of Conservative members, unusual in having a party commitment and thus among the relatively engaged.  Eighty-five per cent of them backed the Government’s plan when polled recently.

A YouGov poll finds “a substantial rise in public support” for the expansion of rights to British National Overseas Passport Holders.  But the firm also finds “a fall in public awareness on the issue”, and wonders whether “it is possible that the Covid-19 pandemic has distracted the public’s attention”.

The Migration Observatory says that public attitudes towards immigration have softened in recent years, but still notes nonetheless that last year “around 39 per cent thought that the level of immigration should stay about the same, while 44 per cent said they would like immigration to be reduced”.

And any recent softening takes place against a hard background: the rise in popular concern about immigration that helped to fuel Nigel Farage and dynamite David Cameron – immigration being the second-most salient issue in the 2016 EU referendum, according to Lord Ashcroft’s polling.

Our take is that the more the Government’s offer is likely to be realised, the faster resistance to it among voters is likely to grow.  Certainly, any influx of workers from Hong Kong must be offset by a reduction in those offered elsewhere.  That is where Johnson’s policy, or that of a successor government, is likely to go, in such an event.

America and China will be rivals for dominance whether Donald Trump is re-elected or not.  It is true that Britain has a responsibility for the Hong Kongers, but it is international as well as national in scope.  Downing Street is reportedly mulling whether or not to push a D10 of democracies to complement the G7.

An early test of the viability of the idea would be for the Prime Minister to champion a multi-national response to China’s aggression – an opening of doors to people from Hong Kong across the democratic world as well as in Britain.  The proposal should nestle in David Frost’s in-tray.