For foreign nationals in Belgian detention centres to be able to return to their country of origin or to another country where they are allowed to stay, they must have the necessary travel documents. The objective of the Immigration Office is to reduce the detention period as much as possible. Early identification is therefore paramount in shortening the return process and the possible detention associated with that process.

A positive identification should result in the issuance of a travel document (the laissez-passer) that will allow the return of a third-country national to be organised.

If, on the basis of the identity documents, there is no doubt about the identity, the Immigration Office can, in certain cases, issue a standard travel document. The basis for this practice is contained in the agreements concluded between Belgium or the European Union and a third country. The identification procedure will then end with the issuance of an "EU laissez-passer".

In practice, it turns out that foreign nationals in irregular stay do not have or conceal these documents, do not want to cooperate in their identification or simply give completely false information in order to make the execution of the order to leave the territory more difficult.

The first step in the identification process is to try to convince the foreign national to present their identity documents. If the foreign national in question still has a valid passport, this will automatically reduce the period of detention with a view to return. If they do not, they will be interviewed to obtain the necessary identity and nationality details, as well as any useful information that helps to determine their real identity. The person concerned will also be asked to fill in questionnaires provided for this purpose by Belgium, the authorities of the country of which they claim to be a national and those relating to the various existing readmission or administrative agreements signed by Belgium and the country of origin.

The embassies or consulates of the countries of origin in Belgium or the competent authorities in the country of origin play a very important role in the process of identifying a foreign national in irregular stay. It is in everyone's interest that the cooperation between the Immigration Office and the competent authorities of the country of origin is optimal. The Immigration Office relies in particular on the help of diplomatic and consular representatives to assist its agents, convince foreign nationals in irregular stay that it is in their interest to cooperate in the identification process, respect Belgian and European laws and directives and comply with the orders to leave the territory that are served on them.