The UK death toll from Covid-19 may pass the 100,000 mark this week, a depressing milestone in the progress of the pandemic. As a proportion of the population this represents one of the worst fatality rates in the world.
This time a year ago the virus was confined to the Chinese city of Wuhan and its environs.
If there was a time to close the borders, it was then, and certainly once the pandemic had been declared by the World Health Organisation.
But it would have taken a government blessed with extraordinary foresight to have done so. In any case, the main vector for the disease appears to have been the many thousands of British tourists returning from Alpine ski resorts in February and March. Should they all have been quarantined at a time when there were few known cases?
With hindsight that might well have have made a difference to the spread of the contagion and it is evident that some ministers were proposing the closure of all borders at the time. But it was politically inconceivable. Moreover, once imposed such controls cannot be lifted. This is the dilemma facing ministers this week as they contemplate a raft of new measures principally designed to stop new variants of the virus entering the country.
The irony of the arrival of a vaccine is that the prospect of a return to normality appears to have receded rather than advanced, with schools now unlikely to reopen until after Easter. Without a vaccine the Government would have no choice but to contemplate scaling back restrictions once cases began to subside.
But ministers now fear that mutations will enter the country and render the various vaccines ineffective. Matt Hancock, the Health Secretary, disclosed yesterday that 77 cases of a virulent South African variant have been identified from travellers into the UK. A small number carrying a Brazilian mutation have also entered the country.
Clearly, stopping all travel not subject to strict quarantine regulations will reduce this risk. But the Government must also acknowledge that, as has been seen with Australia and New Zealand, these are not stopgap measures but semi-permanent controls. The logic of this policy is that for as long as mutations threaten to undermine the vaccine programme then normal travel to and from the UK will be impossible. For a country that relies so heavily on its international connections this is a serious, possibly irrevocable, step.