All-party support for a measure suggests it is a reasonable idea. But that is not always the case, as the suggestions of the new cross-party group on immigration demonstrated yesterday. Its proposal for "balanced migration" – by which it means that the number of migrants into the UK must not be allowed to exceed the number of Britons emigrating – is fraught with practical problems. The proposal that migrant workers should only be allowed to stay in the UK for four years would deter the most skilled incomers who, knowing they will be kicked out after a short time, will gravitate elsewhere. It would also force upon employers the unnecessary burden of re-recruiting for posts which had perfectly satisfactory incumbents.

But the basic problem goes deeper. It is the group's basic premise that immigration is bad for Britain. The truth is the very opposite. The vast majority of migrants are a boon, not a burden, to this country. They do jobs that Britons turn down, such as fruit-harvesting, factory packing, and vital public-service jobs like looking after the elderly in care homes. The National Health Service would collapse were it not for the hard work of migrants.

Of course, immigration does bring some stresses. The rapid influx of foreign workers can put strain on public services in areas where the Government has not provided additional cash to deal with increased demands on local schools and housing. But the solution is for the Government to become better at allocating cash to councils which are under pressure, not a cap on the movement of labour. And we should remember that immigrants give back far more than they take economically. They pay tax and are, largely, barred from claiming benefits. Because they tend to be young and healthy, they do not make huge demands on the NHS.

If ministers want to make a positive contribution to the debate, they will outline funding for more immigrants to improve their English. They will talk about ways to encourage integration and tolerance. "Dog-whistle" politics, in the form of talk about a "tough new points system" or "British jobs for British workers", does nothing but stoke resentment.