In the UK, when you sign the “contract”,it is an indication that on a certain date you will complete the purchase of the house and pay whatever is due, then the deeds will be either given to you,if you pay cash, or held by the bank that took your mortgage for the balance of the purchase price.On the sellers part, it is an indication that he will complete his side of the bargain and hand over the deeds and vacate the property on the day of completion. If either party reneges on the contact, they can be sued for specific performance.