An Agreement in Principle — also called a Decision in Principle — is a lender's statement that, based on soft-checked basics, it would likely lend you a stated amount. It is not a mortgage offer and not a guarantee, but it is the credential that turns you from a browser into a proceedable buyer in an estate agent's eyes. It is the exit ticket from Phase 2.
What an AIP is and is not
The AIP checks your declared income, basic outgoings and a credit search, and returns a borrowing figure typically valid for 30–90 days. It does not verify documents, value any property or commit the lender — a full application can still fail on evidence, affordability detail or the property itself. Treat it as a strong signal, and never as permission to stretch beyond it.
Soft search versus hard search
Most AIPs now use a soft search, which is invisible to other lenders and harmless to repeat. Some still run a hard search, which lands on your credit file and, repeated, damages it. Ask before consenting; if you are comparing several lenders' AIPs, insist on soft search routes.
Timing and accuracy
Get the AIP when you are genuinely ready to view — its validity window is short, and refreshing is easy. Answer every question exactly as you will on the full application: an AIP won on rounded-up income creates a paper trail of inconsistency that underwriters notice later.
Scenario: two offers on the same flat
Two buyers offered the asking price on the same flat within a day of each other.
The first had no AIP and 'would sort the mortgage out quickly'. The second attached an AIP dated that week, named her conveyancer, and confirmed she was chain-free. The agent advised the seller that only one offer was evidenced.
Outcome: The seller accepted the second offer the same afternoon — at the identical price. The first buyer obtained an AIP three days later and asked to be reconsidered; the property was already Sold Subject to Contract. Preparation, not price, decided it.
Your action list
Practical tips
- A broker can usually obtain an AIP the same day from a lender matched to your profile.
- Refresh an expiring AIP before making offers — agents check dates.
What can go wrong
- An AIP is not underwriting: changing jobs, taking new credit or discovering a file problem after it can still sink the real application.
- Multiple hard-search AIPs collected while 'shopping around' can measurably damage the credit file the real application depends on.
- PropertySquares provides education, not financial or legal advice. Verify current rules and obtain advice for your circumstances before acting.