Labour grandee Tessa Jowell has revealed she is being treated for brain cancer and marked her 70th birthday today with a pledge to help people with the disease.

Ms Jowell's illness has not previously been disclosed but she and her family both posted pictures on social media today to celebrate her birthday.

She told MailOnline: 'I'm in treatment at the moment, but will share more soon, and look forward to finding ways to make better, longer lives for people with cancer'.

The Labour politician was a veteran of both the Tony Blair and Gordon Brown governments, raising to greatest prominence as the Minister for the Olympics.

Tessa Jowell's illness has not previously been disclosed but she and her family both posted pictures on social media today to celebrate her birthday (including on her Twitter, pictured)

Neither of today's social media posts made exactly clear Ms Jowell's current condition.

On her own Twitter feed, Ms Jowell said: Thank you for so much love and support on my birthday.

'More people living longer better lives with cancer is my birthday pledge.'

Ella, who is married to Ms Jowell's son Matt, shared a post on Instagram.

She said: 'The last few months have been some of the hardest of our lives, after Matt's Mum was suddenly diagnosed with brain cancer in May.

'Her bravery, optimism, love and support for others during this process has inspired us both so much, and today, on her 70th birthday, we're all pledging to try and do everything we can to make people's lives with cancer better for longer.

'I'm sure so many of you have had to deal with this process too, and Matt and I will work to find new ways of supporting and enhancing people's lives who have been affected.

'Lots of love to you all, Ella and Matt.'