Kaffee Form is a German company that makes coffee cups out of used coffee grounds, collected from Berlin coffee shops and blended with natural glues.
The cups are durable, reusable, dishwasher safe and have good insulation properties, then when no longer of use are biodegradable.
The company also make a takeaway coffee cup with lid called the Weducer Cup.
Cups are available online from their web-shop and in UK from some speciality coffee shops. Check their store locator: https://www.kaffeeform.com/de/store-locator/