One has to be careful about the terms 'legal mortgage' or 'statutory mortgage' as these are used in common law jurisdictions, because their meaning is different (please see the definitions in: http://en.wikipedia.org/wiki/Security_interest).

Here we have a right conferred by statute for a creditor, under certain circumstances, to demand that a mortgage be entered in the land register to secure his/her claim, without requiring the debtor's consent.

Provision is made for the procedure known in Turkish as "kanuni ipotek" in article 893 of the (new) Civil Code:

"Madde 893- Aşağıdaki alacaklılar, kanunî ipotek hakkının tescilini isteyebilirler:
1. Satıştan doğan alacağı için satılan taşınmaz üzerinde satıcı,
2. Elbirliği ortaklığına giren taşınmazlarda paylaşmadan doğan alacakları için birlikte mirasçı olanlar veya diğer elbirliği ortakları,
3. Bir taşınmaz üzerinde yapılan yapı veya diğer işlerde malzeme vererek veya vermeden emek sarf ettikleri için malzeme ve emek karşılığı olarak malik veya yükleniciden alacaklı olan alt yüklenici veya zanaatkârlar. [...]"

The source of the Turkish Civil Code is the Swiss Civil Code, and the source article on which the corresponding Turkish article was based is 837, as anybody knowing French or German will immediately see from the text of this article in these languages:

In French

"837
Peuvent requérir l’inscription d’une hypothèque légale:
1. le vendeur d’un immeuble, sur cet immeuble en garantie de la
créance;
2. les cohéritiers et autres indivis, sur les immeubles ayant appar-
tenu à la communauté, en garantie des créances résultant du
partage;
3. les artisans et entrepreneurs employés à la construction ou à la
destruction de bâtiments ou d’autres ouvrages, au montage
d’échafaudages, à la sécurisation d’une excavation ou à
d’autres travaux semblables, sur l’immeuble pour lequel ils ont
fourni des matériaux et du travail ou du travail seulement, que
leur débiteur soit le propriétaire foncier, un artisan ou un en-
trepreneur, un locataire, un fermier ou une autre personne
ayant un droit sur l’immeuble. [...]"

In German

"Der Anspruch auf Errichtung eines gesetzlichen Grundpfandrechtes besteht:
1.
für die Forderung des Verkäufers an dem verkauften Grundstück;
2.
für die Forderung der Miterben und Gemeinder aus Teilung an den Grundstücken, die der Gemeinschaft gehörten;
3.
für die Forderungen der Handwerker oder Unternehmer, die auf einem Grundstück zu Bauten oder anderen Werken, zu Abbrucharbeiten, zum Gerüstbau, zur Baugrubensicherung oder dergleichen Material und Arbeit oder Arbeit allein geliefert haben, an diesem Grundstück, sei es, dass sie den Grundeigentümer, einen Handwerker oder Unternehmer, einen Mieter, einen Pächter oder eine andere am Grundstück berechtigte Person zum Schuldner haben. [...]"

There exists an official Swiss government translation of this same article:

http://www.admin.ch/ch/e/rs/210/a837.html

"The right to establish a statutory charge on immovable property applies to:
1.
the vendor’s claim to the sale price;
2.
the claims of co-heirs and other co-owners in undivided shares arising from the division of immovable property which belonged to the community;
3.
the claims of tradesmen and building contractors who have supplied labour and materials, or labour alone, for construction or other works, for demolition work, scaffolding work or for securing the construction pit or similar on the property whether the debtor is the owner of the property, tradesman or building contractor, tenant or any other person with rights to the property."

and I think the best course of action would be to go along with this usage.





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Note added at 19 hrs (2013-05-07 09:49:13 GMT)
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The Wikipedia link is:
http://en.wikipedia.org/wiki/Security_interest

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Note added at 1 day18 hrs (2013-05-08 09:03:48 GMT)
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The question as asked is a noun phrase, so that should of course be:
"the establishment of a statutory charge".