Dame Tessa Jowell, the former Labour culture secretary, has been battling brain cancer for the past four months, her family have revealed.

Ella Mills, the food blogger best known as Deliciously Ella, posted a picture of herself with her mother-in-law to celebrate her 70th birthday and praise Dame Tessa's "bravery and optimism."

The former Labour Cabinet minister, who helped secure the 2012 Olympics for London, also posted a message on Twitter pledging to help others with the disease.