On the same day a William Morris tapestry is auctioned at Sotheby's, an 11,000-signature petition to protect his gallery is handed to the council.
Protesters say the museum will be downgraded
Waltham Forest Council is accused of downgrading the building by replacing some staff and reducing opening hours.
Protest organiser Martin Adams said: "It will change from a centre of excellence to a centre of mediocrity."
The council said the petition - presented on Thursday - was out of date and £98,000 in funding had been added.
The museum and gallery is located at Walthamstow in what was Morris's family home from 1848 to 1856.
It was opened in 1950 and houses £60m-worth of his work.
Morris (1834-1896) was an artist, writer, and socialist. He was one of the principal founders of the British Arts and Crafts movement, a pioneer of the socialist movement in Britain, and a writer of poetry and fiction.
He is also well known as a designer of wallpaper and patterned fabrics, and his work fetches high prices at auction.
A tapestry is up for auction at Sotheby's in London on Thursday and the protest petition will be presented to a council meeting the same evening.