because in a way what have you got to lose?

When I was 25 I was a single mum with three small children,

living on a council estate in Brixton.

I decided that something had to change.

But what I didn't realise was that by changing my life,

I also changed the lives of many other women all around the world.

I woke up one morning in 1987

with my husband screaming that he was going to kill us all.

He had threatened me before, but I somehow hadn't taken it seriously.

But as soon as he threatened my children

I just thought, “I'm out of here.”

So I got a suitcase, packed up our stuff.

I put the twins in the double buggy, got my three-year-old daughter,

and we ran down the road.

I phoned up Women's Aid,

and a few hours later I was in a refuge on the other side of London.

I thought, “So what am I going to do now?”

My favourite subject at school was maths.

So I enrolled for a maths course at Southwark College.

And the first day I went in, I was so scared.

I walked into the classroom and it was full of mainly men in suits.

And so basically I was petrified.

But I saw a woman sitting at the back of the classroom,

went and sat next to her.

We became best friends

and in fact we came top of the class at the end of the year.

I did a degree in computing,

then went on to do a PhD,

and eventually I got an OBE which was amazing.

I was really shy growing up,

and I realised that if I really wanted to be successful,

I was going to have to change from being a shy 25-year-old

who was scared to even talk to people I didn't know,

to someone who was much more confident.

I've got a ritual that I do every time before I'm public speaking.

And what I do is…

I go into the toilets, and I will say positive things to myself.

So I'll go, “I'm an amazing person. I can do anything I want to do.”

Or stand in more of a superhero pose.

Just going away and doing that

means that I go on to the stage feeling very positive

and kind of radiating energy.

Last year I was speaking to 17,000 women in tech

at a conference in Orlando in Florida.

And at the end of my talk I got everyone -

so 17,00 women - to say along with me:

“I'm going to change the world.”

And you know what, we can.

Always ask for promotion.

If you think you can go for a promotion, go for it.

Every time I could apply for promotion I did.

In several years I got promoted probably four or five times,

and that actually just massively changed my life

and it enabled me to affect lots of other people's lives

in a positive way too.

I was in a classroom talking to maybe about 15 mums.

And as I was talking I started realising,

"Oh my goodness, I'm getting a hot flush, feeling a bit hot."

I couldn't concentrate

so I thought well I'm just going to tell everyone what's happening

and actually that seemed to help us really bond with each other.

The more that we make ourselves vulnerable,

talk about things that we wouldn't normally expect to talk about,

but just everyday stuff,

helps everyone to realise that we're all human and we all go through this.

I've over the years changed myself by pushing myself forward -

going for things that scare me half to death.

The main message I would have to anybody is

just get out there and do the things you want to do.

You've only got one life. Just go for it.