In my experience the best thing to do always is to accept the offer in writing, leaving your projected start date a way ahead, unless you have already received another firm offer in writing which you prefer to accept. Then if another more preferable possibility which you are waiting for comes up (i.e. you receive a formal offer in writing) you can make excuses and explain that you will not be able to start after all with the first one. What you all need to remember in your careers now is that there is no genuine corporate loyalty any longer, in either direction. Employers have destroyed that generally. All consultancy employers ultimately look at you as a profit contribution centre. They will take you on solely on a whim if it suits them and they can see having a good mark-up out of you. They will drop you like a hot cake in any downturn or economic storm, because they do not want to have continue paying you to sit on the bench. You are just a chattle for them to use for charge-out. Very few consultancies seem any longer to understand that their consultants are their most valuable coporate asset, and the larger they are the less they have any understanding of that, and usually now none at all. It has become all a matter of short-term opportunism, and once you become over 45 or so they will have no compunction about ditching you if it suits them, so that you will then probably be permanently excluded from management consultancy per se. (Don't believe that the ageism legislation will make any difference, because it will not.)It has become a matter of making hay whilst the sun shines. Make as much as you can as soon as possible, before the sun stops shining, which it will. You must become as utterly ruthless with potential employers as they have become with their employees, otherwise you will just allow them to trample all over you.