A stay-in-place form for casting structures from concrete or other curable construction materials comprising: a plurality of elongate panels (1130A, 1130B) interconnectable in edge-to-edge relationship via complementary connector components (1132, 1134) on their longitudinal edges to define at least a portion of a perimeter of the form; wherein each panel (1130A, 1130B) comprises a first connector component comprising a protrusion on a first longitudinal edge thereof and a second connector component comprising a receptacle on a second longitudinal edge thereof; and wherein the interconnection of the panels (1130A, 1130B) to one another in edge-to-edge relationship forms edge-to-edge connections therebetween, each edge-to-edge connection comprising the protrusion of the first panel extended into the receptacle of the second panel by relative pivotal motion between the first connector component of the first panel and the second connector component of the second panel; wherein the first connector component of the first panel comprises at least one secondary protrusion and at least one concavity and wherein the second connector component of the second panel comprises at least one complementary secondary recess and at least one complementary projection; characterized in that, for each edge-to-edge connection, the extension of the protrusion of the first panel into the receptacle of the second panel by relative pivotal motion between the connector components (1132, 1134) causes deformation of at least one of the first connector component of the first panel and the second connector component of the second panel such that resilient restorative forces associated with the deformation of the at least one of the first and second connector components (1132, 1134) retain the protrusion in the receptacle to thereby retain the connector components (1132, 1134) in a locked configuration, and wherein, when the first connector component of the first panel and the second connector component of the second panel are in the locked configuration, the at least one secondary protrusion extends into the at least one secondary recess and the at least one complementary projection extends into the at least one concavity. a plurality of elongate panels (1130A, 1130B) interconnectable in edge-to-edge relationship via complementary connector components (1132, 1134) on their longitudinal edges to define at least a portion of a perimeter of the form; wherein each panel (1130A, 1130B) comprises a first connector component comprising a protrusion on a first longitudinal edge thereof and a second connector component comprising a receptacle on a second longitudinal edge thereof; and wherein the interconnection of the panels (1130A, 1130B) to one another in edge-to-edge relationship forms edge-to-edge connections therebetween, each edge-to-edge connection comprising the protrusion of the first panel extended into the receptacle of the second panel by relative pivotal motion between the first connector component of the first panel and the second connector component of the second panel; wherein the first connector component of the first panel comprises at least one secondary protrusion and at least one concavity and wherein the second connector component of the second panel comprises at least one complementary secondary recess and at least one complementary projection; characterized in that, for each edge-to-edge connection, the extension of the protrusion of the first panel into the receptacle of the second panel by relative pivotal motion between the connector components (1132, 1134) causes deformation of at least one of the first connector component of the first panel and the second connector component of the second panel such that resilient restorative forces associated with the deformation of the at least one of the first and second connector components (1132, 1134) retain the protrusion in the receptacle to thereby retain the connector components (1132, 1134) in a locked configuration, and wherein, when the first connector component of the first panel and the second connector component of the second panel are in the locked configuration, the at least one secondary protrusion extends into the at least one secondary recess and the at least one complementary projection extends into the at least one concavity.