The previous Government wanted to reduce net migration (that is, immigration minus emigration) to the "tens of thousands" over the course of the last Parliament, something that it failed to do.
It is questionable whether the target was an effective response to public concerns about immigration.
The next Government has limited options for restricting EU and non-EU immigration, and it may be more cautious about committing to a single numerical target for something not directly within its control.
Chart 1: Concern about immigration
Concern about immigration being too high has remained at similar levels over the past 25 years, but the proportion of the public identifying it as an important issue has increased proportion of survey respondents believing immigration to be "too high".
Open for business? Immigration from outside the EU
As part of its efforts to meet the net migration target, the previous Government took a range of actions to control immigration to the UK from outside the EU (this being the only aspect of migration directly within their control).
For instance, numerical limits were placed on certain categories of visa, including for skilled workers with a job offer; visas for highly skilled workers without a job offer were abolished; and the options available for overseas students to work after graduation were greatly curtailed.
The result was a sharp fall in migration from non-EU countries between 2011 and 2013. However, the trend reversed in the last years of the Parliament, leaving net migration of non-EU nationals at the same level as it had been at the start.
Chart 2: Net migration by citizenship
Net migration by citizenship, Years ending each quarter, Jun-04 to Sep-14, thousands
In seeking to control non-EU immigration, the new Government could be even more selective about who can enter the UK, how long they can stay, and other conditions.
However, as the last Government discovered, there are trade-offs involved in such an approach. Since most immigration from outside the EU consists of students and skilled workers, further restrictions conflict directly with other policy aims, such as addressing skills shortages, including those in public services, and attracting international students to UK universities.
Further restrictions would thus require the increasing prioritisation of immigration control over other objectives.
EU immigration: out of control?
'Free movement of people' is one of the fundamental principles of the EU, enshrined in various EU Treaties, directives and caselaw. EU nationals do not require a visa to enter another Member State and, provided they are in employment or looking for work, studying, or self-sufficient, no time limit may be placed on their stay.
The result is that, as long as the UK remains a Member State, the Government can only exercise indirect influence on EU immigration by addressing some of the "pull factors" that draw migrants to the UK.
Each of the three main parties has set out ideas for new restrictions on EU citizens' rights to live, work and access benefits in other Member States. Public opinion is quite strongly against EU migrants coming to the UK and receiving assistance, without first having lived here and/or contributed to the system for a while.
Having said that, evidence of benefits tourism is weak. The proportion of working age EU migrants claiming DWP benefits (6%) is less than half the proportion of non-migrants in this age group claiming these benefits (15%).
Furthermore, the scope for 'benefits tourism' by those with no intention of working is already limited, as underlined by a recent judgment from the Court of Justice of the European Union.
The new Government's success in securing further restrictions, particularly on the payment of in-work benefits, will depend crucially on whether it is able to secure support for legislative changes from other Member States.
Moving away from a focus on numbers
The limitations of a blunt target that doesn't distinguish between different types of immigration had certainly been recognised by the end of the last Parliament, for example by the cross-party Home Affairs Select Committee.
The next Government will probably want to leave itself more room for manoeuvre when defining its ambitions for controlling immigration than its predecessor.
Would moving away from a single numerical target alienate public opinion? Not necessarily. We know, for example, that the public is more concerned about certain categories of migrant (such as undocumented migrants and overstayers) than others (international students).
Also, public concerns about immigration are not just about the numbers. Issues such as the extent to which local communities and services are supported in managing the impacts of immigration, the contribution that migrants make to the UK economy and society, and the overall credibility and competence of the immigration system, also matter.
Even in the absence of a target, the new Parliament may be able to demonstrate its responsiveness to public concerns about immigration by looking at some of these wider issues.
An inherently flawed target?
Using net migration as an indicator of progress in reducing immigration has some disadvantages. In particular, it is uncontrollable: flows of EEA migrants, asylum seekers and British nationals cannot be directly controlled by the Government. It is also uncertain. Migration statistics are based primarily on a survey of fewer than 5,000 migrants at UK ports of entry/exit, and are therefore subject to a considerable margin of error. Finally, it may be uninformative. Net migration can give a misleading impression of the size of population turnover and hence the true impact of immigration: simultaneously high levels of both immigration and emigraton would result in low net migration, but potentially significant social change.
- Conservatives: annual net migration in the tens of thousands not hundreds of thousands
- Greens: reject a numerical cap on net migration
- Labour: keep cap on workers from outside the EU
- Liberal democrats: restoration of full entry and exit checks at the borders
- SNP: will support sensible immigration policies that meet economic needs and will seek the reintroduction of the post study work visa
- UKIP: introduction of an Australian style points based system