YESTERDAY the government announced that its planned programme of demanding inbound travellers have a “clear” Covid-19 test will be delayed until next week.

A year into a global pandemic and a government which supposedly has “control of our borders” as one of its highest principles still has minimal virus control at the border.

This failure is not new: the main form of “virus prevention” at the border, the supposed “quarantine” rules have been privatised and are even more half-hearted and ineffective than the “contact tracing” system.

There are two main reasons that, for all its talk of “taking back control” of our borders, Boris Johnson’s government has not tried to control Covid-19 at ports and airports.

The first is that when Johnson or Priti Patel talk about having the “most effective border in the world,” they mean border controls will be a way to control and generally push migrants about.

But the vast majority of international travel involves holiday and business flights, not migrants: the government might be happy to make migrants lives difficult, but are making futile attempts to try to minimise impact on the holiday or business travel industries, even at the cost of allowing the pandemic to run wild.

The second reason is that, even when they have tried to institute some control, they have done it through an ineffective, privatised service, because they have an unshakeable enthusiasm for contracting out public services.

It’s hard to understate how weak virus control is at the borders. Announcing the new “negative tests for entry” plan, Grant Shapps made clear that quarantine is more important than negative test certificates.

Shapps told Radio 4’s Today programme, “A test is a useful tool in the armoury, but it is nowhere near as good as quarantine or self-isolation.”

Shapps made clear that the weakness of tests-for-entry is that a test certificate only shows that “in that moment they don’t have coronavirus” — so people may catch coronavirus in between getting the certificate and entry to Britain. Shapps argued that we need quarantine, which is “a much harsher regime than any form of testing.”

It’s a strong argument and for this reason countries like Thailand, New Zealand and Australia demand international travellers are quarantined for 10 days, with airport hotels requisitioned for this quarantine.

To stop this quarantine system being overwhelmed, international travel numbers have also been slashed.

The general restriction of international travel and firm quarantine systems have been part of very successful virus control in other nations. While these countries still have some outbreaks, they have much lower rates of death and infection than Britain.

But our quarantine regime is the opposite of “harsh.” The weak, privatised Isolation Assurance Service appears to have completely failed to ensure self-isolation of international travellers.

Patel announced the Isolation Assurance Service in June: arrivals at airports are asked for their British addresses. Patel said Public Health England “will undertake checks and ensure that people understand and are following the rules.”

So there is no provision for any actual quarantine at the border.

These checks actually mean Public Health England’s Isolation Assurance Service will “attempt to contact randomly sampled arriving passengers to ensure that they are self-isolating.” In fact Public Health England does not make the calls.

They have been contracted out to Sitel, the US call-centre firm which shares the poorly performing “contact tracing” contract with Serco.

Public Health England would not tell me how much Sitel’s “Isolation Assurance” work is worth and the government has not published details of the contract: Sitel already get £310m for its contact tracing work.

The latest “data on health measures at the border” show the Isolation Assurance Service has minimal effect: Border Force spoke to 1.9m passengers at airports and ports from June to September, taking their details.

Sitel’s Isolation Assurance Service then made just over 150,000 phone calls or texts.

It only made “successful contact” with 67,000 people — around 0.3 per cent of travellers — to check they were “self isolating.”

These contacts could mean replying to a text as well as talking on the phone. After four attempts to contact travellers, Sitel gave up.

In theory if the Isolation Assurance Service find that people have not strictly isolated at home for 14 days after travelling abroad, they will be fined.

I don’t believe fines are an effective way of encouraging self-isolation, but the fact that only 40 fines have been imposed shows that the travel quarantine system only exists on paper.

The lack of isolation by holidaymakers and business travellers may have been central to the second wave: studies of Covid-19 mutations suggest that 50 to 80 per cent of British Covid-19 from September is a strain that first appeared in Spain in the Summer.

To understand the government’s attitude, it’s worth thinking about who is travelling through the borders.

Migration currently stands at around 270,000 a year. But there are around 80 million international flights out of Britain each year. Add the Channel Tunnel and ferries and British people make 90 million trips abroad each year.

So where nations have restricted international travel, it has restricted migration, but has had a much bigger impact on leisure and business travellers.

The government has repeatedly tried to pretend Covid-19 is in retreat, so it can get business back to normal.

It never works, but it keeps trying. Incredibly, it tried to restart the holiday industry last year with the “travel corridors” scheme.

It’s striking that “controlling our own borders” was central to the Conservative manifesto, but virus control at the border barely exists: it seems “border control” is only about making life harder for migrants, not viruses, especially if the Heathrow, holiday or business travel lobbies might be inconvenienced.