Traditionally, royal females who have not had the luck to become queens regnant have been granted very limited roles. They have been expected to look pretty, be discreet, do charitable good deeds, and - if married to princes or kings - be quietly supportive and, above all, fertile.

Since the Second World War, as female expectations and opportunities have risen, becoming a royal woman - and remaining a royal woman - has seemed less and less an attractive proposition.

To be sure, political unions between European countries have often failed in the past, but usually only after relatively brief periods. Denmark and Iceland separated after 130 years; the unions between Spain and Portugal and between Sweden and Norway each lasted less than a century.

In the past, Britons were scathing about the cruelties of the old Roman empire and the excesses of Catholic empire builders such as the Spanish and the French. They convinced themselves that their empire was different and benign because it rested on sea power and trade rather than on armies.

I have had moments where I've felt like, 'I'm going to feel a little guilty if I don't put the baby down for her nap today, but I really need to go to that spin class. And that's good for my health and my mental well-being, so I think the nanny can put her down for her nap, and I'm going to be OK with that.'

I have always done exercise because I was a dancer, and it is probably good for you. I have done yoga consistently.

I've seen so many people - loved ones and colleagues - who jump from one diet to the next, one exercise regimen to the next . I was trying to figure out what were some of the basic things that each of us can build into a lifestyle for good, instead of bouncing from one thing to the next.

The new world economic order is not an exercise in philanthropy, but in enlightened self-interest for everyone concerned.