She was a pioneer and a rule-breaker, an educator, community leader and race relations campaigner who met Nelson Mandela and rubbed shoulders with royalty – but always had time to call out the bingo numbers at a local event or sign a passport photo.

In bright sunshine on Wednesday, a choir from the school Betty Campbell led with distinction sang her favourite song, Something Inside So Strong, as a huge bronze monument to her was unveiled in a Cardiff city centre square.

Campbell was the first black woman to become a headteacher in Wales. Under her leadership, Mount Stuart primary in Butetown, Cardiff, became a model for best practice in equality and multicultural education throughout the UK.

But the joyful unveiling was also important because the monument is the first statue of a real, named woman set up in an open-air public space in Wales.

Campbell’s daughter, Elaine Clarke, said her mother, who died in 2017 aged 82, would have been proud of the monument.

She recalled how as a child growing up in the Tiger Bay area of Cardiff, Campbell had been told that a black working-class woman could never reach the academic heights to which she aspired – but she had proved them wrong.

“This sculpture encapsulates Betty’s legacy of determination, aspiration and inspiration,” she said.

Her granddaughter, Rachel Clarke, said Campbell had “shook up society”, adding: “She was ahead of her time.”

She said Campbell had watched Mount Stuart being built brick by brick and was sure she was the person to lead it, even though other candidates had “looked the part”.

During her time at Mount Stuart, Campbell was inspired by the US civil rights movement and taught her pupils about slavery and black history. Later she became a member of the Home Office’s race advisory committee, worked for the Commission for Racial Equality and helped create Black History Month.

Another granddaughter, Michelle Campbell-Davies, said there were still too few teachers of colour and the education system was letting down students from black, Asian and minority ethnic backgrounds. But she called the statue a “beacon of hope.”

Campbell-Davies said that following the Black Lives Matter movement, statues were an emotive subject. “Seeing a statue of a black Welsh woman means that change can happen,” she said.

Helen Molyneux, the founder of Monumental Welsh Women, which is planning to put up five statues of inspirational women over the next five years, said: “Betty’s impact during her life was incredible, but, as with so many women throughout history, likely to be forgotten or overlooked by future generations unless something was done to bring her to people’s attention.”

The sculpture was commissioned following a “Hidden Heroines” campaign organised by Monumental Welsh Women, broadcast on BBC Wales. Campbell topped a public vote to decide who should be the subject of the first statue of a named, non-fictionalised woman in Wales.

There were gasps, beaming smiles and tears as the statue in Central Square, close to the Principality Stadium and not far from Butetown, was revealed.

The sculptor Eve Shepherd said it had been a “total privilege and honour” to create ithe statue. “I hope this sculpture is a fitting tribute to Cardiff and Tiger Bay, the richly diverse community in which Betty grew up in and loved,” she said.

A commemorative poem called When I Speak of Bravery was composed for the unveiling ceremony by Taylor Edmonds, the Future Generations Commissioner for Wales’s poet in residence. It concluded: “Let them come/from far and wide, to see/how just one woman can touch/so many lives.”