Illustration: Simon Bosch When the change comes in, the visa terms will last for two years or four (instead of just four as at present), applicants will need at least two years' work experience (which most already have), they will need to speak English (which most already do) and it will be somewhat harder for them to transition to becoming permanent residents. The number of occupations for which the visas are available will shrink from 651 to 435. But workers in many of the occupations being cut (turf growers, blacksmiths, deer farmers, auctioneers) don't use the scheme anyway. In the year to May 2016 there were no imports of futures traders, funeral directors, archaeologists, or shoemakers either, at least none using the 457 visa scheme. Like Hawke, Turnbull is keener to be seen to be doing something (the word "seen" appears in his transcript three times) than to actually do it. And with good reason. Temporary visa schemes have been and remain a lifeline for Australia.

457 visa worker Yuhwa Kim from South Korea and bakery owner Andreas Rost. Credit:Peter Braig At the peak of the mining boom we were importing 34,500 temporary workers every three months. Without them we wouldn't have been able to expand anything like as many mines simultaneously. Only some of the new workers were employed in mines. But that doesn't mean the mining boom didn't create the need for them. Just as the 1850s Victorian gold rush created a shortage of teachers and lawyers in Melbourne, the West Australian iron ore rush created a shortage of cooks to work at McDonald's in Port Hedland. Prime Minister Malcolm Turnbull with Immigration Minister Peter Dutton. Credit:Alex Ellinghausen The locals who would have once flipped burgers fled to the mines. The Education Department was unable to get cleaners in Karratha. There weren't enough obstetricians. During boom times, temporary migrants make things work.

When times are bad, fewer come. Just like that. What's not to like? In recent times we haven't been granting that many 457 visas, because we haven't needed to. And skilled migrants have been less keen to come. In the past financial year we granted just 85,611 of the soon-to-be-renamed 457 visas. They accounted for 0.7 per cent of the workforce. Which isn't to say they weren't important. Try finding Australian doctors who'll work in the outback. Far more important, and just as flexible, are migrants from New Zealand who can come in on unlimited so-called 444 visas. During 2015-2016 we granted an extraordinary 1.9 million 444 visas to migrants from New Zealand, which isn't bad for a country of 4.8 million. Many would have been multiple entries, and many would have been replacing earlier migrants who had left (as would many of the 457 visas granted).

During the boom, New Zealanders flooded here. Since then the tide has ebbed. During the year to June 2016 more Australians moved to New Zealand than the other way around. Australians worried about population growth would be wise to examine total growth rather than the relatively tiny number of temporary workers on 457 visas. At the peak of the first mining boom, population growth reached 2.2 per cent as immigrants on all sorts of visas made a beeline for Australia, and as Australians who would have otherwise left stayed at home. It's now a less-impressive 1.4 per cent as foreigners have become less keen to move and Australians more keen to leave. So reliable is net migration as a barometer of economic health that the chief economist in the Department of Industry uses it as shorthand for how well things are going. Right now they're not going that well. The populations of Western Australia, South Australia and Tasmania are barely growing. NSW and Queensland are doing little better. But Victoria is racing ahead at a rate not seen for decades. In just the past year Victoria has gained an extra 127,500 residents. It has housed four out of every 10 new Australians.

Despite the fears of some, it hasn't cost Victoria jobs. Employment in Victoria is growing faster than in any other state. And not only employment – job vacancies are growing more quickly as well. The boom in jobs is both encouraging migrants and other Australians to move to Victoria (especially Melbourne) and creating (on the face of it) as many jobs as it fills. It won't last, just as Western Australia's boom didn't last. But when it falters migration to Victoria will slow. That's how migration works. The skilled temporary 457 visas were migration at its most useful. That's why they're staying, in all but name.