There are three common types of agreements that you can enter into when purchasing land for development:
A Purchase Agreement is the most straightforward. This is usually used where the required planning permission is in place and there are no legal or practical issues preventing the carrying out of the development.
If you do have concerns over the land you are looking to buy, or if planning permission has not yet been granted for it, a Conditional Contract can be entered into. This allows you to secure the land on the condition that permission is granted or that any other criteria are met.
For more complicated land transactions, there are Option Agreements. These allow you to secure the site for a fixed period of time to carry out complex investigations from ground investigations to planning. The price for the land on such agreements can be fixed or the price could be a percentage of the market value of the land once planning permission has been granted.