Casting of internal features within a product

A method of forming a cast product comprising:

• providing a core having a plurality of sections and one or more gaps there-between, the core including a first insert member spanning the gap between adjacent sections of the core, both ends of the first insert member extending partially into adjacent sections of the core, and the first insert member being directly connected between the adjacent sections of the core so as to hold the adjacent sections in a fixed relative position, the plurality of sections being formed of a ceramic material;
• locating the core within a mould;
• introducing a liquid phase metal material into the gap between the core sections;
• solidifying the liquid phase metal material in the gap so as to form a cast feature of a resulting solid product;
• and
• removing the core sections from the solid product to form cavities therein such that the first insert member remains securely held within the feature located between said cavities.