Conditional vs Unconditional Property Auction: What Buyers Must Know Before Bidding

Two Different Legal Commitments

The term "property auction" in the UK now covers two distinct types of sale with fundamentally different legal implications for the winning bidder. Many buyers — particularly first-time auction buyers — do not understand the difference until they have already committed. This guide explains both types clearly.

Unconditional Auction (Traditional Auction)

The traditional property auction format, used by auction houses such as Allsop, Savills, Clive Emson, and SDL Auctions, operates on the "hammer price" principle. When the auctioneer's hammer falls and the lot is declared sold:

• Contracts are exchanged immediately
• The buyer must pay a 10% deposit on the day
• Completion typically occurs 20–28 days later
• The buyer is legally bound from the moment the hammer falls

This is a firm, unconditional commitment. If you win the lot and subsequently cannot complete — your mortgage falls through, your survey reveals catastrophic problems, you change your mind — you lose your deposit and may be liable for the seller's costs and losses beyond that. The seller can also pursue you for specific performance.

**Implications for buyers:** You must have your legal due diligence, survey, and mortgage offer (or cash) arranged before bidding. The legal pack (available from the auction house in advance of the sale) must be reviewed by your solicitor. Never bid on a traditional auction lot without having read the legal pack.

Conditional Auction (Modern Method of Auction)

The "Modern Method of Auction" (MMoA) — used by iamsold, GOTO Auctions, and many online platforms — operates on a fundamentally different basis. When the auction ends:

• The winning bidder pays a non-refundable reservation fee (typically £5,000–£6,000 plus VAT, or 4–5% of purchase price in some cases)
• The buyer and seller then have a defined period — usually 28 days — to exchange contracts
• A further defined period (typically another 28 days) follows to complete
• During the reservation period, a survey and mortgage application can be arranged
• If exchange does not occur within the defined period, the reservation fee is lost

The reservation fee is charged to the buyer in addition to, not in lieu of, the purchase price. On a £200,000 property, a £5,000 + VAT reservation fee costs the buyer £6,000 which is not recoverable if the transaction does not complete.

**Critically:** The conditional auction is not a guaranteed sale. If the buyer's mortgage is declined, or the survey reveals problems serious enough to make the buyer walk away, the reservation fee is forfeited. The seller can then re-market the property. Sellers sometimes prefer the conditional format precisely because the reservation fee compensates them if buyers drop out.

Comparing the Two Formats

What to Do Before Bidding on Either Type

**Obtain and read the legal pack.** All reputable auction houses publish a legal pack for each lot. This contains the title documents, searches, special conditions of sale, and any known issues with the property. Your solicitor should review this before you bid, regardless of auction type.

**Arrange finance in advance.** For unconditional auctions, you must have a mortgage offer or verified cash funds before bidding. For conditional auctions, you should at minimum have a Decision in Principle and an assessment of your mortgage eligibility.

**Understand the full cost.** In addition to the purchase price and deposit (or reservation fee), auction buyers typically pay: buyer's premium (charged by the auction house, often 1–3% plus VAT), solicitor's fees, survey costs, SDLT, and Land Registry fees.

**Research the property independently.** Property Passport UK shows EPC ratings, flood risk classifications, sold price history, and tenure information for properties in England and Wales — useful context before committing to any purchase.

Guide Prices Are Not Valuations

Auction guide prices are indicative only. A property with a guide price of £150,000 may sell for £200,000 or more in a competitive room; one with a guide of £300,000 may fail to meet its reserve and be withdrawn. Guide prices are a marketing tool, not an independent valuation. Always establish the property's market value through comparable sold prices before deciding your maximum bid.