Change the way in which property is bought and sold in England

I would like a legally binding contract in place at an earlier stage (for example when a price is agreed) during the property buying and selling process. This will give the seller the confidence to start spending money on their next purchase, and not be worrying about if the buyer is going to back out. If a buyer then backs out without good reason then they will be liable for all the costs that the seller has incurred, and the buyer should also lose their deposit.