Galeria Heavy Carvable Modelling Paste 250 ml from Winsor and Newton.
This is the do-it-all version that is tough and fully carvable. It remains flexible on a variety of surfaces. Suitable for multiple layers. Formulated to have the least effect on colour change from wet to dry. May be over-painted.
Colour may be added directly to modelling paste (note that colour will become lighter and more ‘chalky' and the resulting paste will have reduced body).