We’ve become used over the past seven years to hearing home secretaries announcing ever more punitive policies on immigration at Tory conference. First Theresa May, then her successor Amber Rudd, seemed to believe that it was impossible to overestimate their party faithful's appetite for draconian new rules to drive migration down. But today, something strange happened, that revealed quite how much politics has shifted in the last few months. Rudd barely mentioned immigration at all. And, between the lines, she suggested the May Doctrine on immigration is over.

Since the Conservatives came to power in 2010, the government has proudly vaunted its increasingly harsh migration policies. As home secretary, May, of course, made it her signature theme: from creating the “hostile environment”, complete with "Go Home" vans, to railing against universities who sought to make their institutions hospitable to foreign students, to the infamous man who couldn’t be deported because of his pet cat (sic). Her successor Amber Rudd apparently picked up the tune with gusto. This time last year, she disturbingly pledged to make companies keep a register of the EU migrants they employed.

At a time when the party faithful need rallying after a bruising general election, and when Rudd is rumoured to be mulling a tilt at the Conservative leadership, we might have expected more red meat on immigration restrictions. After all, government policy is firmly to end free movement (even if the precise timings are still unclear). And there is still the whole of non-EU migration to double down further on. But strangely, no such announcements were forthcoming. Ms Rudd instead announced that the government would “consult” on forthcoming immigration legislation, and that she had commissioned the government’s migration experts to provide evidence to form the basis of policy.

To the untrained eye, that announcement might sound so bland as to barely worth noticing. But students of Tory migration policy since 2010, on the other hand, will have sat bolt upright. Because there are three implications from Ms Rudd’s non-announcement. Together, they suggest that the May Doctrine on immigration is dead.

Firstly, the net migration target was not even mentioned. For seven years the government has sought to drive net migration down to the tens of thousands – and for seven years, it has come in for constant criticism. Opponents, including IPPR, have pushed back against a completely arbitrary number. The net migration target treats all migrants the same: a refugee is the same as an EU worker in the NHS, or a Brit returning from a period overseas. Last year, an IPPR report found the government could be getting the numbers wildly off – potentially miscounting international students to the tune of tens of thousands a year. Most of all, it succeeded only in driving up concerns around immigration while failing in its own terms to bring it down. Until today, the government had stuck to it. But Rudd’s silence on the net migration target suggests one of the hallmarks of May’s time in government is being quietly shelved as a policy failure.

Secondly, Rudd pledged to “take decisions based on comprehensive new evidence”, following a series of expert reports she has commissioned from the Migration Advisory Committee. Again, to the uninitiated this may sound innocuous. But immigration policy under May has consistently rejected expert evidence – to the extent that the Home Office allegedly suppressed nine reports showing immigration did not drive down wages. May had expounded an ideological insistence that there is only so much immigration a society can take – and that the UK was far beyond it. The implication of Rudd’s statement is that migration policy will be driven by evidence, not ideology. Implicitly, Rudd has sidelined another totem of the May Doctrine.

Thirdly, and most significantly, Rudd’s speech suggests that she realises the Tories have got as much mileage as they can from bashing immigration. The Tories haemorrhaged support in June among the young, the urban, ethnic minorities and those who are comfortable with immigration. The talk at their conference this week is of little else than how to win these voters over. By skating over migration, Rudd is signalling that, to her, the Tories’ future does not lie in doubling down on her boss’s hallmark policy of ever tougher attacks on migration.

It wasn’t explicit. Amber Rudd hasn’t splashed it in a 4,000-word essay in the Daily Telegraph like Boris Johnson. But, more subtly and with less flourish, the home secretary told Tory conference that Theresa May’s vision isn’t the one guiding Tory policy.

Chris Murray is a research fellow at the Institute for Public Policy Research. He tweets @ChrisMurray2010.