A plastics-coated paperboard carton blank comprises an end part for forming a bottom end closure of the carton; the end part comprises first, second, third and fourth end panels (6-9) whereof the first and third end panels (6,8) are for forming outside panels (6,8) of the end closure and the second and fourth panels (7,9) are for forming inside panels (7,9) of the end closure; the free end portion (12) of the third end panel (8) is cut out at both sides in a laterally symmetrical manner with respect to its middle, so as to leave a central tongue (17), and the free end portions (11,13) of the second and fourth panels (7,9), respectively, are cut out at their sides adjacent to the third end panel (8), so as to form respective cut-outs (36,40); and the cut-outs (36,40) have respective edges (32,34) thereof which are further from the tongue (17) disposed obliquely relative to adjacent edges (42,44) of the respective cut-outs (36,40) and diverging outwardly relative to each other.