Half a million refugees who poured into Germany in the past 18 months have failed to register with authorities.

Officials say this means they are either working on the black market or have plunged into the criminal underworld to get money because no registration means no benefits.

Either way, officials are deeply worried about the numbers and are expected to discuss the issue at a cabinet meeting with Chancellor Angela Merkel tomorrow.

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Half a million refugees who poured into Germany in the past 18 months have failed to register with authorities

Syrian refugees arrived yesterday at the camp for refugees and migrants in Friedland, Germany

'Many migrants do not register because of a fear that they may be sent back,' said an interior ministry spokesman.

The Federal Criminal Police office (BKA) will present a report entitled 'overview on the situation' to Mrs. Merkel and her lieutenants about the huge numbers of asylum seekers who have vanished off the radar.

The BKA, which collated the numbers, will report also that crime by immigrants is mostly commited by refugees from Balkan countries - Syrians, Iraqis, and Afghans 'barely feature in the crime statistics,' according to a spokesman.

The BKA has also completed an overview of the events in Cologne on New Year's Eve when bands of immigrant men, mostly asylum seekers from North Africa, sexually molested and robbed hundreds of women in and around the city'v main train station.

The Federal Criminal Police office (BKA) will present a report entitled 'overview on the situation' to Mrs. Merkel and her lieutenants about the huge numbers of asylum seekers who have vanished off the radar

Protester hold banners as they demonstrate against deportations planned at the port of Mytilini, Lesbos

This single episode served more than any other event to polarise society, rip the welcome mat from under the refugees and galvanise right-wing parties to pose a real threat to Mrs. Merkel at the general election scheduled for next year.