They are common, throwaway comments – we are being inundated by immigrants, they are coming to every town and destabilising our economy and way of life. But these statements are rarely backed up by facts or figures. Here, we look at the most recent figures available from the Office of National Statistics and ask what the effect of immigration really is.

A popular statistic is the ‘population of 70,000,000’ – the assertion that the population of Great Britain will soon reach that figure. It is true that in 2031, the population of the UK as a whole is predicted to be 70,933,000 but Great Britain won’t catch up for another two years. Before we look at how migration factors into these predictions, lets have a look at other influences on this figure: Falling birth rates, the ageing population and the large number of people born between 1945 and 1960.

The birth rate in the UK is already below the 2.075 children per woman replacement rate, and is expected to fall further, to about 1.83. This means that the average age of the population is getting higher – part of the reason people are going to need to work into their 70s in the near future. This in itself will reduce the population. As the people born between 1945 and 1960 begin to pass away, the rate of population increase begins to taper off.

So where does immigration fit into this? Net migration – what is left when the emigration figure is subtracted from the immigration figure – currently stands at about 198,000 per year, from all sources. This is expected to drop off to about 180,000 per year from 2016 onward. This is not because of an increased number of emigrants: Gross long-term migration is falling by about 30,000 people year on year. Pinning down an exact number of non-British Citizens living in Great Britain at any one time is difficult for a variety of reasons: Firstly, there is a continuous inflow and outflow of people from the country, including non-British Citizens going both ways. Secondly, at least half of the non-British Citizens living in the UK are from the European Union, meaning they are more difficult to account for as they do not need visas and tracking through National Insurance numbers is more complex.

It’s difficult isn’t it, assessing the impact of immigration? ’70 million economic migrants’ sounds great as a sound bite, but it doesn’t begin to tell to whole story. Statistics mean nothing in isolation, but that is often how they are presented, along with an emotive statement. All the figures here come from the latest reports from the Office of National Statistics; it’s not exactly bedtime reading, but it’s where the real truth about migration is to be found.