Żelfix po Angielsku?

I have a Polish cake recipe which requires żelfix and I am in England at the moment. Does anyone know what this is in English? The recipe says to add four packs of żelfix which seems a little excessive? I just need it to keep the double cream firm on my trzybit. Maybe icing sugar?

Żelfix is pectin with sugar. You can find pectin under various brand names close to jams and marmalades in supermarkets. You could also try substituting with gelatin, which has a somewhat different texture. You can also use potato starch as a gelling agent, but it won't congeal until heated.