Last night, former Immigration Minister and Labour MP Barbara Roche, Liberal Democrat peer Lord Dholakia and I launched Migration Matters.

Immigration became an issue of increasing public concern during Labour’s period in office and in one sense it’s easy to understand why. Net immigration from outside the EU (that is the number of people coming into the country from outside the EU minus those leaving for non-EU countries) increased significantly. There was also significant migration from within the EU, particularly from eastern Europe following the last Government’s decision not to apply accession controls. And there was strong evidence that many people were coming here illegally and that people who were found to be here illegally were often not being removed.

The combination of these three effects has given rise to a number of concerns.

Some people are concerned about the overall numbers and their impact on public services and the demand for housing. The UK saw rapid population growth and because the impact of immigration was concentrated in certain parts of the country and there wasn’t sufficient investment in infrastructure in those areas it did undoubtedly lead to pressures.

Some are more concerned about who we let in and the economic impact on certain sections of society. There is some evidence that because a significant proportion of those who came here had relatively low skills they ended up competing with the unemployed for work and driving down wages at the bottom end of the labour market.

And some are concerned about the cultural impact of this change - rightly or wrongly, they feel that migration has changed their area in a way that they don’t feel comfortable with.

It is right that politicians address these concerns.

But another cause of the rising concern about immigration is the way the issue is discussed in our media. What’s my evidence for this? Well, there is very little correlation between the level of concern about immigration in different parts of the country and the actual levels of immigration in those areas, suggesting that people’s concern is driven not by what they see happening in their area but by what they believe is happening across the country as a whole based on what they hear or read in the media.

And in recent years much of that discussion has been based not on evidence but on a prejudice that all immigration is bad.

That needs correcting. And that’s why we’ve set up Migration Matters. Barbara, Navnit and I come from different political traditions. We’re not necessarily going to agree on the detail of policy. But we are united in wanting to see a nuanced debate that recognises the benefits of immigration as well as addressing the problems.

And if anyone reading this is in any doubt about what those benefits are, I would give three examples.

First, on a personal level many of my friends, neighbours, the activists who helped to get me elected, the people who deliver public services in Croydon, the people I meet when I visit charities and community organisations in the borough are first or second generation migrants. My life would be immeasurably poorer if they or their parents had never come here.

Second, at the moment the biggest challenge facing this country is to reduce the deficit and get the economy growing again at the same time. There is clear evidence that net migration boosts GDP (though not necessarily GDP/head) - indeed, the OBR forecasts on which the Chancellor relies are based on this assumption.

Third, the OBR has produced a fascinating report which shows how net migration can buy us more time to deal with the costs of an ageing society.

So yes let’s talk about immigration. Let’s address people’s concerns. But let’s do so based on the evidence, not a false assumption that all immigration is bad - an assumption which damages our prospects of winning the global race which the Prime Minister so rightly says we are involved in.