Among the stuffed shirts of Lincoln's Inn, Ms Kingsmill is seen as an outsider. She supports the Labour party, she allows herself to be photographed with her clients and - horror of horrors - she talks to journalists on the record.
Most irritating of all, she has an enviable client list, including Sir Patrick Sheehy of BAT Industries and Peter Wood of Direct Line fame. For a long time, she represented George Walker, who faces fraud charges in connection with the collapse of Brent Walker.
Instead of quietly staying with the same firm for 40 years, the incorrigible Kingsmill has already worked her way through no less than five, not counting the spell when she worked for herself.
Now she has parted company with Clyde & Co after just 16 months.
Clyde's chief executive, Ian Milne, tells me the relationship 'didn't quite work out as we had expected and hoped', but the parting was 'amicable'.
Kingsmill, meanwhile, is devoting her energies to winning the franchise to run the national lottery. She is a director of Rainbow, one of eight groups pitching for the coveted licence.
'After all the years of acting for other entrepreneurs, I thought I'd have a go myself,' she says. She is taking a six- month sabbatical from private practice, keeping on just a few select clients like Stein.
'If we don't win the licence, I'll go back into private practice,' says Kingsmill, adding that she has already lined up the stand-by employer. She won't say who, but it is not one of her past firms.
Rainbow is one of the more secretive bidders, wisely not even attempting to out-Branson Branson by seeking publicity. The chairman is Sir Patrick Sheehy. The chief executive is Richard Wheatly, chairman of the Leo Burnett advertising agency, with whom, incidentally, Kingsmill has struck up something of a romance.Reuse content