From Knit Today:

This lovely lace sweater is knitted in Debbie Bliss Fine Donegal, a fine tweed 4 ply ideal for delicate knits and lacework.

Yarn:
4 / 4 / 5 / 5 / 6 x 100g balls in Teal (15)

Yarn alternatives:
Robin 4ply cone yarn
King Cole Bamboo Cotton 4ply