Blathwayt and her mother started attending meetings of the Bath Women's Suffrage Society.
In July 1906, Blathwayt gave three shillings to Women's Social and Political Union (WSPU).
She first met Annie Kenney at a WSPU meeting in Bath and agreed to help Kenney, Elsie Howey, Clara Codd and Mary Phillips to organise the women's suffrage campaign in her area.
Blathwayt was given an allowance by her family to support her in her work for women's rights.
 Many women who supported the cause bought merchandise supporting the WSPU such as 'branded' china or brooches, and in Blathwayt's diary she had bought tea (tea leaves) which she had to return to Bath WSPU - as it was 'off'.
Blathwayt met many of the key people from the suffragette movement who were invited to stay at her parental home and to plant a tree to celebrate a prison sentence.

However when Vera Wentworth and Elsie Howey assaulted the Prime Minister this proved too much for Mary Blathwayt's family.
Her mother, Emily, resigned from the WSPU and her father, Linley, wrote letters of protest to Christabel Pankhurst, Howey and Wentworth.
Pankhurst was told that Howey and Wentworth could not visit their house again.
Wentworth sent them a long reply expressing regret at their reaction but noting that "if Mr. Asquith will not receive deputation they will pummel him again".
Blathwayt and her mother started attending meetings of the Bath Women's Suffrage Society. In July 1906, Blathwayt gave three shillings to Women's Social and Political Union (WSPU). She first met Annie Kenney at a WSPU meeting in Bath and agreed to help Kenney, Elsie Howey, Clara Codd and Mary Phillips to organise the women's suffrage campaign in her area. Blathwayt was given an allowance by her family to support her in her work for women's rights.  Many women who supported the cause bought merchandise supporting the WSPU such as 'branded' china or brooches, and in Blathwayt's diary she had bought tea (tea leaves) which she had to return to Bath WSPU - as it was 'off'. Blathwayt met many of the key people from the suffragette movement who were invited to stay at her parental home and to plant a tree to celebrate a prison sentence.
However when Vera Wentworth and Elsie Howey assaulted the Prime Minister this proved too much for Mary Blathwayt's family. Her mother, Emily, resigned from the WSPU and her father, Linley, wrote letters of protest to Christabel Pankhurst, Howey and Wentworth. Pankhurst was told that Howey and Wentworth could not visit their house again. Wentworth sent them a long reply expressing regret at their reaction but noting that "if Mr. Asquith will not receive deputation they will pummel him again".
Mary Blathwayt