Gayatri Devi: Indian princess who combined the life of a socialite with an outspoken commitment to political action

One morning in February 2008 a group of Jaipur's poorest residents protesting about the city's developers getting their hands on their Sanjay Nagar slum area were surprised to be joined on the pavement by Gayatri Devi, queen mother of Jaipur, who had joined them from her lodge in the Rambagh Palace grounds a few miles away.

The land had belonged to her late husband, Maharaja Sawai Jai Singh, and had been put in trust with the government of Rajasthan for the residents of the city. But, Devi had complained firmly in a letter to the local police, a boundary wall had been removed, trees cut down and the property mafia was moving in. "The land where the Sanjay Nagar slum settlement is located once belonged to the royal family and most of the residents there now are former staff of the royal household," she added firmly.

The defiant gesture brought the Rajmata, then aged 88, huge national attention, the more so for being made in a state that was rapidly being overwhelmed by India's economic push-me pull-yous: illegal land grabs, a city population swelled by agricultural workers no longer able to make a living in the rural areas, and a sudden explosion of high rise buildings and shopping malls.

It also reminded India that she remained in many senses the country's queen mother-general, a princess of Cooch Behar in the North-east, who had become by love match the third wife in 1940 of the Maharaja Sawai "Jai" Man Singh II of Jaipur and who, while being celebrated by American Vogue as one of the most beautiful women in the world, remained committed to the welfare of her poorest subjects.

Gayatri Devi, Ayesha to her family (her mother was reading Rider Haggard's She during pregnancy), was one of the few remaining scions of a royal house which spanned nearly a century of the country's history, based on the belief that the bond between rulers and subjects espoused the best of princely rule (a third of India was ruled by the princely states at the time of independence) and was in content more socialist than Congress and Nehru's five year plans. It was the family's good standing in the years before and after 1947 – and particularly her husband Jai's intention that the integration of Jaipur into India should be a smooth one – to which calm communal relations between the Hindu and Muslim communities after the Jaipur bombs of May 2008 may partly be attributed.

While some of the Rajasthan princes openly took sides in the violence of Partition, Jai insisted that his care for his subjects was equal regardless of religion. There were no riots in his state in 1947. "When some Muslims wanted to leave Jaipur during the communal disburbances, he stopped them and told them, 'No Muslim should leave Jaipur and go. They are all like hair on my chest'," recalled his Muslim gardener. "The Muslims did not forget this."

As a young woman, growing up in the carefree atmosphere of one of India's most relaxed royal families, Gayatri Devi had always demonstrated a philanthropic streak. Nicknamed pagh rajkumari or "mad princess", she was concerned about the welfare of the palace servants, taking persistent interest in how much they were paid and how they were housed. In married life, and despite such luxuries as habitually taking the Jaipur Dakota plane to Delhi to have her hair done (Jai eventually said this had to stop), and pioneering fashions for French chiffon saris and double strands of pearls, her concern for the poor continued.

In India the Sanskrit code of behaviour for ruling princes went back to the Arthashastra, written in the 4th century BC. It stated that a ruler must serve his people's needs, provide for their welfare and deal with injustice. Fourteen years after independence, and in opposition to Nehru's stagnated Congress party, Devi ran with Chakravarti Rajagopalachari's then liberal-centre Swatantra party for the Lok Sabha, or lower house. She was elected in 1962 by a world record landslide majority – 192,909 votes out of 246,516.

Her presence in parliament was to the great irritation of Indira Gandhi. In the 1930s they had both attended Patha Bhavana, the school founded by Rabindrinath Tagore, but Mrs Gandhi hated princely privilege even more than her father. Devi, like many of Gandhi's opponents both real and imagined, spent several months in the infamous Tihar Jail during the Emergency. Here she gave lessons to the prison children and played cricket and football with them, despite serious gallstone problems.

Although she said in later life she would have been offended not to have been imprisoned by Gandhi, her bravery was very real. As she recalled in A Princess Remembers (1976): "My stepson brought me home from prison and asked me what I'd like to do. I said I'd like to take a bath, get into fresh clothes and then meet Pappu (Navin) Patnaik. My son told me that the place was bugged, to which I replied, 'I'd like to meet Indira Gandhi then.' Needless to say, he was horrified!" Placed on parole, Gayatri could not participate in the elections of 1976. None the less when Gandhi's son Sanjay was killed in an air accident in 1980, Devi telephoned Gandhi to offer condolences. She refused to take the call.

Devi had suffered bereavement and family problems herself and there was worse to come. Her beloved Jai had died in 1970, suffering head injuries after a fall while playing polo at Cirencester. Their only son Jagat, whom Mark Shand described as "the dazzling prince with flowing locks and flashing eyes, attired in jewels and jeans, turban and T-shirt" died from alcoholism in 1997. Family feuds – there had been children from Jai's two previous marriages – succession battles and legal wranglings dominated the last 25 years of the Rajmata's life and were unresolved at her death.

The Rajmata remained active in her philanthropy however. As well as administering the Sawai Jai Singh Benevolent fund which was set up to help the poor of the state of Jaipur with monetary, medical and housing aid, she had opened the Maharani Gayatri Devi Girls Public School, which has the highest reputation in India and which celebrated its diamond anniversary six years ago. In April 2003 she pledged payment for the treatment of Ali Abbas the 12-year-old brought to London from Iraq after severe injuries sustained in the US/British invasion.

In 2004, Eastern Voice voted her the fourth most beautiful woman of the last century. Her face, it was thought, was better known to most Indians than that of their president.

Born in London, she spent five to six months a year here in the last decades of her life and always presented the Cooch Behar Cup at the Cowdray Polo Club in Sussex. She was in London during her final illness, but insisted on being flown back to Jaipur in mid-July. She received a state funeral.

Catriona Luke

Gayatri Devi, Rajmata of Jaipur, philanthropist, politician: born London 23 May 1919; married Sawai Man Singh II of Jaipur (one son, deceased); died Jaipur 29 July 2009.