Last reviewed: June 2026
TL;DR- A mortgage in principle (MIP) - also called an agreement in principle (AIP) or decision in principle (DIP) - is a conditional indication from a lender that they would consider lending a specified amount.
- It is not a formal mortgage offer and does not commit the lender to lend - full underwriting, valuation and documentation checks follow in the full application.
- Some AIPs use a soft credit search (no impact on credit score); others use a hard search (visible to other lenders for 12 months).
- Most estate agents and sellers expect buyers to have an AIP before accepting an offer - it signals financial readiness.
What a Mortgage in Principle Includes
A mortgage in principle is a preliminary assessment by a lender of how much they would be willing to lend, based on the income and basic credit information provided at the time. To obtain an MIP, the borrower typically provides: gross income; the type of employment (employed, self-employed, contractor); the required loan amount and deposit; and consent to a credit check. The lender produces a conditional indication - "in principle, subject to full application and valuation, we would consider lending £X."
The MIP is usually valid for 30-90 days. It does not guarantee the loan will be approved at the full application stage - the full assessment involves employment verification, income documentation, credit file review, property valuation and the lender's full underwriting process.
Soft vs Hard Credit Searches
Different lenders and brokers use different types of credit search when generating an MIP:
- Soft search: visible only to the borrower when checking their own credit file. Does not affect the credit score and is not visible to other lenders. Suitable for initial research without commitment.
- Hard search: recorded on the credit file and visible to other lenders reviewing the file for 12 months. Multiple hard searches in a short period can negatively affect the credit score. Appropriate when the borrower has identified a specific property and is committing to an application with a specific lender.
Borrowers should confirm with the broker or lender whether the MIP process uses a soft or hard search before consenting to a credit check.
How Much Weight Estate Agents Place on an AIP
Most estate agents ask buyers for an AIP before presenting their offer to the seller. An AIP demonstrates that the buyer has taken preliminary steps to confirm their financing and is a credible buyer rather than a speculative one. A seller is more likely to accept an offer with an AIP than one without, particularly in competitive markets. Some estate agents treat AIPs from well-known lenders more favourably than those from less familiar names, though what matters to the seller is ultimately the strength of the overall offer.
Limitations of the AIP
An AIP is not a mortgage offer and is not a guarantee of lending. Reasons a full application may be declined after an AIP include: the income documentation does not match what was declared; the credit file reveals issues not apparent from the initial check; the property fails the valuation; the property type does not meet the lender's criteria; or the applicant's circumstances have changed between the AIP and the full application. Borrowers should be transparent with the lender or broker at the AIP stage to avoid disappointment at the full application.
Frequently Asked Questions
Is an AIP the same as a mortgage offer?
No. An AIP is a conditional preliminary indication; a mortgage offer is a formal, binding commitment from the lender (binding on the lender - the borrower can still decline). A mortgage offer follows a full application, documentation verification, credit assessment and property valuation. An AIP is the first step; a mortgage offer is the conclusion of full underwriting.
How many AIPs should I get?
Getting AIPs from multiple lenders generates multiple hard searches if hard searches are used, which can negatively affect the credit score. It is generally better to use a broker who can identify the most suitable lender and obtain one AIP from that lender, rather than approaching several lenders directly. If soft searches are used, multiple AIPs have no credit score impact.
Does an AIP mean I can definitely borrow the amount stated?
No. The AIP amount is indicative and subject to full underwriting. The actual offer may be the same, more or less than the AIP amount depending on what the full application and valuation reveal. The AIP provides useful guidance for property searching but should not be treated as a certainty.
Can I use an AIP from one lender and then get a mortgage from a different lender?
Yes. An AIP from Lender A does not commit the borrower to use Lender A. After finding a property, the borrower can proceed with a full application to any lender - including a different lender from the one who issued the AIP. The AIP is simply a preliminary market test, not a commitment by either party.
