What is a key undertaking or key release arrangement?
Why keys sometimes release only after telegraphic transfer confirmation and how undertakings reduce the risk of buyers occupying before funds clear.
Published: 18 Apr 2026 · Updated: 18 Apr 2026 · 8 min read
Property Passport UK
See this information for your own home
Free address search across England and Wales. No account needed.
19.4 million searchable properties. EPC, flood risk, sold prices, planning, and more in one structured record per home.
Summary
Key release is sequenced with completion mechanics so sellers are paid before buyers take possession; undertakings formalise how agents or solicitors handle that moment safely.
What to do next
Write down questions as they arise and share them in one message thread with your solicitor to reduce ambiguity.
Property Passport
Permissioned sharing reduces duplicate email chases during a transaction.
Using Property Passport UK
Start from the address on [Property Search](/search). When you own or manage the home, [claim your Property Passport](/claim/start) and upload Documents with clear dates and sources. Browse more explainers in the [Property Guides library](/guides). This article is general information, not legal, tax, mortgage, or survey advice.
Essential Buying a Property guides
Related guides
What is a joint borrower sole proprietor arrangement at a high level?
9 min readWhat is a key undertaking on completion day?
9 min readPublic Passport vs Owner Dashboard (What Each Is For)
6 min readWhat to Check When Buying a House, 12 Things to Verify Before Exchanging Contracts
10 min readHow Long Does Conveyancing Take, and What Causes Delays
6 min readWhat is Exchange of Contracts, and Why It's the Point of No Return
6 min readRelated calculators
Search any property in England & Wales
EPC ratings, flood risk, sold prices, and planning data — free, instant, no login required.