No contract until start date!?!

[bfg]

I would never start before a signed contract was in place

Read your PI and PL insurances, no contract in place and you're not covered for a start!

[hattra]

Verbal Contract

Theoretically, if you start without a written contract, you (and they) are bound by what has been verbally agreed, and as supported by any other written evidence, like the job advert, any correspondence between the parties, etc. (Which is why its good to have a general set of Ts & Cs that you can email off at the beginning of serious negotiations)

If you answer an advert for a VC++ contract, agree to do it, and then get put onto something else, and start without a written contract, then the other party cannot hold you to any notice terms etc. or other conditions that they impose retrospectively. Of course, you also cannot force them to give you VC++ work, so all you can do is either walk, or take them to Court for compensation (which I wouldn't recommend, particularly if you are only supplying services, as it probably wouldn't be worth it).

Of course, if they then produce an unacceptable written contract, and you simply turn up at work, without stating which bits you disagree with, in writing, then I suspect that any Court would simply say that you had implicitly accepted the new written contract