Barely keeping her head above water, Miranda Richards was once juggling a high-stress City career, multi-million pound deals, childcare, her marriage and an – at times overwhelming – sense of guilt.

Fast-forward 10 years and the whirlwind mother-of-four enjoys a slower pace of life in north Norfolk.

And now her previous lifestyle, with all its dilemmas and competing demands, is the inspiration behind a best-selling novel which has been turned into a film, I Don't Know How She Does It, starring Sarah Jessica Parker.

Miranda, who lives in Briningham, near Fakenham, was once torn between the love she had for her job as a fund manager and her young family.

She recalls sneaking out of meetings to call home, missed parents' evenings, tearful goodbyes as she left on often-weekly business trips abroad and an inevitable sense of unease as her daughters grew increasingly attached to their nanny.

Watching a preview of the movie, Miranda was in tears as the protagonist Kate Reddy sings down the phone to her toddler.

'I remember being away in America and realising it was 8pm at home and the girls' bedtime,' she said. 'I would try and find an empty office so I could call them to say goodnight and yes, I did sing to them.

'But I enjoyed my job because I knew I was good at it. It was tiring, but it was fun. Luckily I had a husband, Nick, who was based in the UK and he's been incredibly supportive.'

Kate is based on Miranda and has the same job, but incidents in the novel are based on the experiences of a number of working mothers.

The novel, by her close friend Allison Pearson, opens with Kate desperately 'distressing' shop-bought mince pies rather than admit to the other parents at her daughter's school that she didn't make them.

'That wasn't me – I would have been up making the pastry from scratch at 1am,' laughed Miranda. 'To me, I was doing what everyone else was doing.

'I thought it was perfectly normal. Every working mother has a war story or two to tell. When the book came out, several of my friends phoned and said 'is this about me?'

'Ten years ago I think there were an awful lot of women trying to do all that juggling without that juggling being acknowledged. It was never talked about then, now it's common parlance. I think the book brought the issue out in the open.

'Now for a working woman, I think it's easier to say I have to leave at 5.30pm for my son's nativity. Most women have the confidence to say 'my children are an integral part of my life'. Part of the reason is because men's attitudes have matured.

'Men are wanting to be part of the parenting process so much more than when I was in the City and that's a really positive thing. The introduction of better maternity packages and flexible working has also been a huge help.'

What hasn't changed, Miranda believes, are the difficulties women face when they want to return to work after a career break.

'Some do struggle,' said Miranda, who proudly wore a dress from Holt boutique Anna at the film's premiere in New York.

'What you have been doing is disregarded as irrelevant, which is extraordinary. Women then lower their expectations and that's a huge waste.' Nick's family has had a home in Sheringham for more than 40 years and the couple visited Norfolk for many years before finally buying a house of their own ten years ago.

Miranda, who was born and bred in Newcastle, requested to go part-time following the move and left her job while pregnant with her fourth daughter Honor, who is nearly nine.

'I felt circumstances had changed sufficiently that I couldn't carry on,' she said.

'The book had just come out and I knew it was going to be a big deal. I didn't know how my employer would feel.

'I miss having my own salary and – it's going to sound quite vacuous – the sense of self-worth you get from working in an office, even if it's just 'that dress looks brilliant.'

'But I don't miss the office politics and the idea that if I'm going to get on in my career I'm going to have to go and sit in the bar.'

Having initially planned to take it easy, Miranda was soon involved in a number of projects and in village life.

Today, she works two days a week in London, is a school governor involved in several charities and is secretary of Briningham PCC.

'I'm extremely busy, but I love it,' she said.

Miranda also has more time to spend with her older daughters Polly, 16 and Milly 14, who attend school in Rugby, and 12-year-old Theodora, known as Bee, who attends Beeston Hall in West Runton, near Cromer, with younger sister Honor.

So with the benefit of hindsight, is it possible to have it all?

'I think if you want to have it all, you have to accept that sometimes ok is good enough – it can't all be perfect.'