Sophie would, of course, need to disclose her own assets and would doubtless be keen to ensure these were ring-fenced for the future. If all goes wrong, she may want the option of returning to her flat in Coleherne Court; certainly she would want to protect her interest in her PR company and feel able to build upon that for her personal benefit. She would therefore want to ensure that all the assets she brings to the marriage would remain hers, whatever may happen in the future, and that she would retain full control over them.
In due course she will be receiving a number of gifts, some very personal, others in the form of engagement or wedding presents. Some careful drafting would be needed to ensure that she would retain a fair share.
At present Edward holds Bagshot Park under a lease from the Crown Estates. Sophie may feel that the lease should be placed in their joint names to give her the reasonable security and protection that most wives would be seeking - the Crown Estates may have a different view.
She would also, one suspects, like to be sure that in the event of any disaster befalling Edward, she would have the right to continue to live there - especially if there are children to provide for. A formula could be devised providing that funds are put in place and made available to her as and when there is a family to provide for.
It may not be appropriate to put it in the agreement (and it could be a little premature) but it may be no bad thing if Edward and Sophie could clear the air on how they expect to see their children brought up and educated.
Sophie's style and cost of living is likely to rocket. Depending on her own resources she could reasonably expect financial help to cover additional transport and clothing allowances and fashion or style advice. She would, perhaps, be asking for staff to assist her in managing Bagshot Park and provide her with transport and protection when needed. The royal family have some experience in this area.
Sophie and Edward should certainly agree to make appropriate wills. Sophie would want to ensure proper financial protection for herself and any children if Edward should die before her.
The view seems to be that this relationship is one that really can work and last. If, however, it fails disastrously quickly and there are no children, then Sophie will face some rapid readjustments and may well be looking for some reassurance about her future financial position. (So may Edward.)
The key to all this is likely to be the extent to which Edward can expect to receive funding from royal resources and to what extent financial security will be put in place "up front" - and just what sort of constraints the royal advisers would be imposing on any funds that were provided. There would be a good deal of work to be done to steer a fair and sane course through very delicate territory.
The writer is a partner in the law firm Collyer-Bristow.