I”˜ve written before about the difficulty of having a sensible discussion about immigration policy, but the vital importance of doing so - so I am very pleased that Nick Clegg and Simon Hughes are bringing a proposed policy to party conference next month about it (and have also written about it in Liberator).

For a long time discussion of immigration found it very difficult to escape from a context of racism. I think the fact that in recent years much immigration has come from other European countries, rather than other continents, has done a lot helpfully to disentangle the two.

The other thing that seems to have changed is the sheer numbers of people coming into the country. I don’t at all say that that is necessarily a bad thing - but it quite clearly is a significant change and an important issue, and any sensible discussion about our society and country clearly can’t ignore it.

The motion seems to me a good starting-point for a serious discussion, untainted by racism, of the sort of way that we want Britain to develop, economically and culturally, and what role immigration has in that.

That’s all about the formal legal position, and those who have permission to live in the UK. But one of the features of this debate is the large number of people who live in the UK outside the system, and without permission.

There is a real dilemma here - the formal position of the government is that anyone who does not have permission to live in the UK will be deported - but the problem is that, although certainly some people are removed from the UK, nobody believes that this will actually seriously address this problem as a whole. But simply granting an amnesty would be in danger of simply encouraging more illegal immigration in future.

And stuck in the middle of this dilemma are at least many hundreds of thousands of people (nobody seems to know quite how many) who live in this country but outside its law, without any of its protections.

The proposal in the motion seems very sensible to me - not simply granting a blanket amnesty, but encouraging those who want to commit to being part of the UK, down a route which will allow them to do that, and gain legal immigration status. The fact that someone has to have been here for several years before they can go down this route seems to me a useful safeguard against it encouraging new large waves of migration of people seeking to take advantage of such a system.

I’m also pleased that, in the wake of the row provoked by some comments by Margaret Hodge a few months ago, the motion calls for a ”˜full review’ of social housing allocations policies ”˜so that those who have waited a long time for a home or a home transfer are treated fairly’ - combined with a ”˜a major programme of building social housing to tackle housing shortages for all those in need’.

I’m very pleased that this motion is going to conference. There is a reason why mainstream politicians have often been shy of talking about this issue in public in recent years - it’s a sensitive issue and relatively easily open to misrepresentation - but I’m very glad that as a party we are challenging that and talking about this important issue.