Mortgages can be agreed in principle so you know that you can get the mortgage you require before you put offers on your new home. Your Agreement in Principle will be the first document provided to you by your mortgage lender which shows any prospective seller that you can actually get a mortgage to cover the purchase price. This can include the lender checking your credit rating and confirming the amount you can borrow. A useful thing to have before you start any serious property hunting.
This is an agreement from a mortgage lender given to an [applicant] showing whether they are willing to offer an [applicant] a [mortgage] or not
a commitment from a lender that they will lend you a specified amount, as long as the property you find is suitable and you are able to verify your income
an agreement from a mortgage lender that in principle they will lend you a specified sum for property purchase (as long as any property you buy is satisfactory and that you are able to verify the income you have declared)
an agreement from a mortgage lender that in principle they will lend you a specified sum for property purchase (subject to valuation of the property, verification of income and confirmation of any other checks they require)
This is an initial agreement to the borrowing you've requested. It's a good indication that, based on the information provided as part of your application and subject to other information such as a valuation report on your property, we will be able to offer you a mortgage.
if your mortgage is agreed in principle by a lender it means that they are prepared to lend to you provided certain requirements are met.