The firm would then be informed of the ways in which your work will be compromised by the legal department's stipulations. A request should also include testimony as to the value of having those constraints removed. This alternative demonstrates professionalism, affords you the opportunity to conduct your work they way you want to, and is the only way to gain leverage over the intransigent legal department. The third alternative is to walk away from the project. This alternative would prevent you from violating your own ethical code. Also, it would prevent you from being forced to turn in substandard work. There would be a small hit to your professional pride about not finishing the work you were hired to do, but ultimately as a consultant you must have control of your methods, resources and outcomes in order to be effective.

Recommendation

The first alternative is the weakest of the three, and should not be exercised. The output will be poor, which damages your reputation. Moreover, it will compromise your ethics. There are no winners with the first alternative, except perhaps a company with some things to hide that merely wants a code of conduct for cosmetic purposes.

The second alternative respects your personal ethics and business reputation because you attempted to salvage the situation. Future clients will understand that not all situations can be salvaged, but you did not quit until there was no other option. Moreover, the second option may prove successful. The human resources manager and senior executives may not be aware of the legal department's actions and may not approve of them. If you are able to reach them and win their support, you can use their power over the legal department as leverage to back the legal department off and allow you to conduct your task as you see fit.
Should the second alternative fail, the third alternative should then be exercised. As a consultant, you are measured by your output and as a person you measure yourself by your ethics. The integrity of both must be maintained, even at the cost of the income from this job. The third alternative should only be used as a backup to the second, because to quit right away would show a lack of professionalism that could ultimately hurt your business.