Are legally binding loan agreements which have to be registered at the Land Registry. See above. Because they are designed to protect the lender and make sure they get their money back should you be unable to repay the loan, the lender wants to be certain they are legally watertight. For that reason they will use a lawyer to look after their interests. Usually they are willing to use the same solicitor as you as this cuts down on the duplication of work. We act for all the major lenders. Your mortgage offer will almost certainly contain a condition that you pay the cost of the legal work involved in looking after the lender. How much this will be depends a little on the lender involved and the size of the loan but guidelines agreed between the major lenders and the Law Society put the legal costs for most mortgages at around £150 to £400 plus VAT.