A newly-discovered drawing by British sculptor and artist Henry Moore sold at auction for £25,000 having been bought in a charity shop for a few pounds 20 years ago.

The drawing features four studies of a mother and child, a common theme in Moore’s work, who was one of the most important British sculptors of the 20th century.

The same sale saw a pen and ink drawing by Lucian Freud that had been torn to pieces by the artist and restored sell for £6,930 to a different private collector in the UK.

The woman who purchased Moore’s drawing at a charity shop thought it was just a print but when it was taken out of its frame during a routine valuation at Forum Auctions, Moore’s signature was found and another drawing was discovered on the reverse.

It was sent to the Henry Moore Foundation and after two years of research Four Studies for Seated Mother and Child was confirmed as being created by Moore.

The drawing was sold on Thursday at Forum Auctions to a private UK-based collector and will be featured in the Moore foundation’s upcoming catalogue on Moore’s portfolio.

The images on both sides were created in Moore’s trademark mixture of inks, watercolour and wax crayon between 1947 and 1949.

One side features four studies of a mother and child seated and the other shows a delicate, larger depiction of a single version of the image in muted hues of yellow and blue.

Commenting on the sale of the work, Eleanor Garthwaite, specialist at Forum Auctions, said: “We are delighted with the result of this newly-discovered drawing by one of the most important British artists of the 20th century.

“Works by Henry Moore are always highly sought-after and this was witnessed today by competitive bidding from around the world.”

Moore was born in 1898 in Castleford in Yorkshire and attended Leeds School of Art and the Royal College of Art in London.

By the 1930s he was one of the most important working sculptors in Europe but switched to drawing after his Hampstead home and studio was bombed at the outbreak of the Second World War.

A mother and child is one of Moore’s most recognisable motifs and his increased focus on the subject is notable during the war period.

The Lucian Freud work that sold on Thursday titled Still Life With Plant was created by the artist in the 1940s and was purchased for £90 by the current owner from the artist’s agent.

Freud later ripped up the drawing, but the fragments of the image were enclosed in an envelope and reconstructed by a conservator.