The migrant crisis is at the top of the agenda around Europe. Here we look at the key questions.

East Anglian Daily Times: Migrants show placards outside of the railway station in Budapest, Hungary, Thursday, Sept. 3, 2015. Over 150,000 migrants have reached Hungary this year, most coming through the southern border with Serbia, and many apply for asylum but quickly try to leave for richer EU countries.(AP Photo/Frank Augstein)Migrants show placards outside of the railway station in Budapest, Hungary, Thursday, Sept. 3, 2015. Over 150,000 migrants have reached Hungary this year, most coming through the southern border with Serbia, and many apply for asylum but quickly try to leave for richer EU countries.(AP Photo/Frank Augstein)

What has led to the crisis in Europe?

An unprecedented surge in migrants arriving from the Middle East and North Africa. Conflicts in Afghanistan and Syria, as well as a repressive regime in Eritrea, are seen as major factors in what charities have described as the worst refugee crisis since the Second World War. UK ministers have claimed that a large proportion of the people arriving are “economic” migrants looking for work rather than fleeing persecution.

How many people are arriving?

The EU’s border agency Frontex said the number of migrants detected at EU borders in January to July stood at nearly 340,000. This was almost three times higher than the 123,500 recorded in the same period last year, and already higher than the 280,000 detected in the whole of 2014. The true scale is likely to be higher as the figures do not include those passing into the continent undetected.

How many people have died trying to reach Europe?

The latest estimates suggest there have been more than 2,600 fatalities as migrants attempt to cross the Mediterranean, often in rickety, overcrowded boats.

Where do they come from?

Syrians, Afghans and Eritreans are generally seen as making up the bulk of the arrivals.

What routes do they take?

The three most common routes are known as the eastern Mediterranean, the western Balkans or the central Mediterranean.

Where do they go next?

Germany receives by far the most asylum applications in the EU, and is expecting an extraordinary 800,000 refugees to arrive this year.

In July, the most detections were reported in the Aegean Sea, with nearly 50,000, mainly on the Greek islands of Lesbos, Chios, Samos and Kos. Italy received more than 20,000 migrants in the month. In the western Balkans, Hungarian authorities detected more than 34,000 arrivals.

What about the UK?

Estimated figures show that Britain had the seventh highest number of asylum applications within the EU in the year to June, with 33,000 including dependants. Germany had almost eight times as many, with 259,000, followed by Hungary (93,000) and Sweden (78,000).