Not going to get involved in speculating, but your own personal needs are what should guide your decision. Regardless of your beliefs in what might happen in the future or not, you need to make decisions on what you need, and what is happening. If the future phase is in a location you prefer, and you are willing to take the risk of waiting, then wait. However, there is a planned .25 point ECB rate rise expected soon. Consider that also.
Also consider if you are happy with your current home - if renting, will your rent go up? If in some other arrangement (if you are HTB you are usually an FTB) will that last? Either way, you still need a home.