The European Union’s (EU) failure to deport the vast majority of illegal migrants arriving by boat is a “pull factor”, encouraging the treacherous journey across the Mediterranean, a Brussels official has conceded.

Economic migrants crossing the Mediterranean, who have no right to be in the EU, have a 73 per cent chance they will be permitted to stay, official figure show.

Since the beginning of the migrant crisis, there has been a surge of migrants from relatively safe nations, overtaking those from war-torn nations such as Syria, who were initially encouraged to come by the EU.

“The inability of EU governments to enforce deportations is the biggest pull factor,” a Brussels diplomat working on migration blasted. Speaking to The Times, he added:

“If people know that as illegal immigrants they have a 70 per cent-plus chance of being able to stay, even if ordered to leave, then it is hardly surprising people get into the boats.”

The European Commission records a “rate of effective return” to non-EU countries of just 36.4 per cent, which falls to 27 per cent when returns to the western Balkans are taken out.

In 2016, the largest group arriving were Syrians. In the first half of this year, however, the largest group (14,120) came from Nigeria – a relatively safe nation with the largest economy in Africa.

Whilst 98 per cent of Syrians were awarded asylum, just 21.7 per cent of Nigerians have been.

Guinea, Ivory Coast, and Bangladesh were the next largest sources of migrants crossing the Mediterranean this year, with Syria down at number five.

Most irregular migrants arriving in Spain so far in 2017 were from Ivory Coast, Guinea, Gambia. See our updated map https://t.co/UCde8h1fyc pic.twitter.com/ebMyJt1HVb — Frontex (@Frontex) August 22, 2017

An EU-led mission in the Mediterranean, Operation Sophia, was also slammed by Libya in April this year for “encourag[ing] the migration” across the Mediterranean towards Europe.

NGOs and left wing charity-run migrant rescue ships have come under pressure, too, after claims they were colluding with people traffickers and picking migrants up just off the Libyan coast.

North Africa and Libya, in particular, is now the main departure point after the EU agreed on a deal with Turkey to send migrants arriving in Greece back to Turkey.

Italy has became the main arrival point, with Spain becoming increasingly popular, such that is likely to attract more sea-arrivals this year than Greece.