sculpture network start'19 in Royal Society of Sculptors, London:

We'll be celebrating with a family-friendly drop-in workshop!
How many materials can you use in one sculpture? It’s up to you! Join us at the Royal Society of Sculptors and be inspired by our current exhibition to make your own crazy sculptures. Use a wide variety of materials to build your work, and if you get stuck grab a creative chance card to help with your ideas and try something unexpected!

Free. No need to book.