Reality Check: Will there be migration of 275,000 a year until 2035?

The claim: Net migration to the UK will be an average of 275,000 a year until 2035.

Reality Check verdict: All such forecasts involve huge uncertainties. Migration Watch's predictions are higher than the Office for National Statistics ones, but not as high as a forecast from Vote Leave.

Migration Watch has released its predictions of what will happen to migration to the UK if it stays in the European Union.

The think tank that campaigns for reduced levels of migration to the UK gives a headline figure of average net migration of 275,000 a year for the next 20 years.

It is an average of figures for two different scenarios, both of which assume net migration (that is people coming to the UK for at least a year minus people leaving) will fall from the 2015 level of 333,000.

The "low" figure assumes that:

• migration from outside the EU (over which the UK has more control) falls from 188,000 in 2015 to 100,000 by 2020 and stays at that level

• 5,000 of the refugees currently arriving in Europe end up in the UK in 2020, rising to 20,000 by 2028

• gradual declines in migration from elsewhere in the EU

The "high" figure is based on:

• non-EU migration of 150,000 a year

• considerably more of the refugees arriving in Europe ending up in the UK

• smaller falls in migration from the rest of the EU

Neither figure has Turkey joining the EU in the next 20 years, which seems sensible given the obstacles in the way of its EU membership.

Migration Watch says that if Turkey did join, it would increase net migration by 30,000 a year for the first seven years, while transitional controls were in place, and 100,000 a year after that.

There are huge uncertainties involved in all such predictions, but it is worth looking at how Migration Watch's forecast compares with others.

The Office for National Statistics (ONS) sees net migration falling from its current levels to 185,000 per year by 2020 and staying there, giving an average over the period of just over 190,000 per year.

Migration Watch thinks the ONS has been undercounting migration from the EU, rejecting its recent explanation for the difference between the numbers of National Insurance numbers being given to EU nationals and the migration figures.

Vote Leave released a much higher estimate, the "medium" forecast for which has net migration just from the EU rising to 339,000 a year by 2030, but that assumes that Albania, Macedonia, Montenegro, Serbia and Turkey all join the EU in 2020, which few people believe will happen.

Read more: The facts behind claims in the EU debate