washing powder 
noun [mass noun] British
Detergent in the form of a powder for washing clothes, bed linen, etc.As members arrived at our March meeting a generous collection of soap, toothbrushes, flannels, sponges, washing powder etc., gradually piled up....
- They don't take up much room in your case and I was told not to use cheap foreign washing powder as it can be too harsh and damage your clothes by making lighter colour bleached patches on them!
- Despite having been running around a stage for an hour playing a guitar previously, he was clean and his clothes radiated the smell of washing powder.