Rehearsal: Dancers prepare for the show at Jo Richardson School

The story of warring New York City gangs that changed musical theatre forever is being produced at Jo Richardson School in Dagenham.

The school in Gale Street is showing West Side Story, which took Broadway by storm in 1957 before being immortalised by Hollywood four years later.

Fifty-five singers, dancers and musicians star in the production, based on the book by Arthur Laurents, with music by Leonard Bernstein and lyrics by Stephen Sondheim.

West Side Story tells the tale of Tony and Maria, who fall in love despite being from opposing teenage street gangs, the Jets and the Sharks, and are from different racial backgrounds.

Caroline Cook, 48, school head of drama, said: “West Side Story was groundbreaking. It changed the state of musical theatre.

“There was more dance and it was edgy. It dealt with serious stuff.

“The audience is going to go away with tears in their eyes – it’s heartbreaking.”

Jo Richardson School had to purchase a copyright from the US producer who created the Broadway musical in 1956, Jerome Robbins.

Ms Cook said the musical was given a “generous budget”, owing to its high production values, including elaborate lighting and costumes.

Twenty-five students have also been working behind the scenes creating the backdrop and promoting the show.

Three school departments – music, drama and dance – have been working on the musical since autumn 2011.

Ms Cook said the scale of the show was so big, a piece of theatre of this size could only be put on every two years.

She added: “The school community will benefit from it. Students will all remember how they felt when they did the play.”

West Side Story is on at 7pm this evening and tomorrow. It is open to students, parents and the public.

Tickets cost £5 for adults and £3 for under-16s. For more information call the school on 020 8270 6222.