if you go to the local council website of the property in question, they usually have a planning section. From there you can look at plans, and whether they have been approved or not
I went onto our local council website recently and went to the planning section, as bednobs suggests, and was able to enter the address I was interested. I found a complete history of all planning applications which had been submitted for the site in question and the exact status of each one, as well as details of the relevant correspondence and the Plans.