The plaque was mounted largely at the instigation of Dr Sarah Hellawell, lecturer in modern British history at the University of Sunderland, who campaigned for it.
Dr Hellawell said: “I was left surprised that so few people have actually heard of Marion Phillips.”
Indeed, Dr Phillips is one of those historical figures who should be better known. So who was she?
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Her main relevance to Sunderland is that she became its first female MP at the 1929 general election; the first election in which women’s voting rights were equal to men’s.
She was actually born in Melbourne, Australia in 1881, but moved to the UK in 1904.
She graduated from the London School of Economics before working on the Royal Commission into the Poor Laws, researching public health, medical relief and the treatment of destitute children.
This helped create the welfare state in the 1940s, providing a safety net for society’s very poorest.
In 1911, she assumed leadership of the Women’s Labour League, promoting the representation of women in parliament before they had even been given the vote.
She held a number of significant roles during World War One and in 1918 became Labour’s first chief woman officer, a role she retained until her death.
In this role, Dr Phillips travelled the country and was a regular visitor to the North-East, attending the women’s rally in Durham.
In 1926 she visited Ryhope Miners’ Hall and donated a christening gown and shawl to a struggling mining family who were expecting a baby. In return, the Barnes family christened their daughter Marion Phillips Barnes; now 93 and still living in Sunderland.
In July 1928 Dr Phillips sent a letter to all women in the town, stressing the importance to them of the 1929 General Election, due to its extended suffrage.
At the time of the election, Sunderland was a difficult seat for Labour, despite being predominantly working-class. Nevertheless, she won and was one of only 14 female MPs in the parliament.
She hadn’t actually intended to stand for parliament, but felt compelled to accept the nomination on behalf of women and the poor.
The first woman to sit as an MP in parliament was another feminist icon, the Conservatives’ Nancy Astor in 1919. The two did not get on.
Dr Phillips’ story doesn’t end happily. Along with all other female Labour MPs, she lost her seat at the 1931 election, beaten by Conservative Samuel Storey; grandson of Sunderland Echo founder Samuel Storey snr.
Three months later, Dr Phillips died of stomach cancer.
Her relevance to feminism is undiminished. Despite a record 211 female MPs now and two women Prime Ministers, only 494 women have ever been MPs.
And whatever your views, it’s nice to remember a conviction, rather than career politician, such is their increasing paucity.
For the crime of possessing a serious demeanour and rimless glasses, in 2019 she would inevitably be described as “sour-faced” and reports of her arguments with Nancy Astor appended with the word “miaow!”