The Labour government is already consulting on creating an Urban Development Corporation (UDC) for greater Cambridge. The consultation opened on the 4th feb and closes on the 1st April (April fools).
The UDC creates a top down approach from government. What it wants, it will get.

Planning, in this country, has always taken local views into account, however frustrating that might be to some. The system is not perfect but the UDC will run roughshod over all of us.
The area runs right up to Haverhill. I suspect it is this that is giving encouragement to the Forest City idea.
Please have a look at the consultation and reply as best you can. It is a little daunting I’m afraid. if you struggle with the online forms you can send your thoughts by email to GCDCconsultation@communities.gov.uk