The hard Left’s focus on past rather than present slavery tells you everything you need to know about it.  It would rather mobilise to smash statues than protest outside foreign embassies.  Or even the Home Office.

For over 10,000 people were referred to the authorities in Britain over modern slavery last year.  But its scale in this country is tiny compared to elsewhere.

Anti-Slavery International estimates that 40 million people are slaves worldwide, that almost three-quarters of them are women, and almost a quarter children.

So there is a strong feminist and child protection element to the cause.  And an emphatic recent history of Conservative Government activism over it, driven by Theresa May, though we are only in the foothills of progress.

Her Modern Slavery Act of 2015 consolidated and updated previous offences.  It was crafted to target the most common form of slavery in Britain, forced labour, more effectively and to put those responsible for it behind bars.

In 2016, there were 74 convictions under previous leglisation and only one under the act.  By 2018, the balance had change to 23 and 21.  So the overall number of convictions actually fell between those years.

Part of the explanation will be that forced labour by way of sexual exploitation, domestic slavery or, say, in a nail bar or car wash isn’t easy to find.

Anti-Slavery International refers specifically to Vietnamese nationals forced to work in cannabis factories, but the overall problem isn’t restricted to the exploitation of migrants, legal or illegal, or even recent arrivals.

Nor is the problem found in or exported from the non-western democracies alone.  In the 15 years to 2017, 200,000 children were married in the United States, including three ten year old girls and an eleven year old boy.

None the less, the Global Slavery Index caculates that 62 per cent of modern slavery worldwide is to be found in Asia or the Pacific.

A worldwide map shows hotspots in Mauritania, Afghanistan, South Sudan, the Central African Republic and North Korea.  There is also a problematic mass of countries running south-east from Myanmar.

Essentially, modern slavery is most prevalent in most forms outside Europe – Government-forced labour, prison labour, sex slavery, prison labour, and so on.

Though the forced labour estimates are topsy-turvey, with the Index, which puts Europe and Central Asia together, providing 91 per cent of forced labour.

(Turkmenistan, Belarus, and Macedonia are the countries recorded to have the highest prevalence overall.  Russia, Turkey, and Ukraine have the highest absolute number, accounting for over a third of victims.)

The forced labour category returns one to Britain, where the issues are not resolved, any more than modern slavery itself has been eradicated.

For the slaves themselves, knowingly or unknowingly, will often have entered illegally – which necessarily sparks debate on protecting victims as well as removing illegals.

So control of our borders is a necessary though not sufficient policy component.  An independent review praised the Modern Slavery Act as “world-leading” measure, but went on to criticise parts of it.

In particular, the review said that 40 per cent of companies within its scope aren’t complying with the legislation at all, and that penalties against non-compliant organisations have not been used.

Furthermore, many companies treat their new obligations as “a mere tick-box exercise”.  We suspect the same may be true of the mass of goals and indicators in the Government’s own modern slavery statement.

Progess will mean grinding, detailed, attritional work – the kind that the far left and extremist parties aren’t interested in undertaking and aren’t capable of doing anyway.

Mainstream politics is better set up for it and the Conservatives have a good story to tell so far.  Now they must build on what May left them.