The short answer
An audit trail is a log of each step in the signing of a document: when it was sent, viewed and signed. It is tamper-evident when the log is built so any change to it shows. It is evidence, not a guarantee. Nothing can promise how a court will weigh it, but UK law allows electronic signatures and records to be used as evidence, so the real question is how convincing yours is.
What it records
- Who was asked to sign, and how they were reached, such as a link sent to an email address.
- A timestamp for each view and each signature.
- A fingerprint of the document, so anyone can check that the PDF is the one that was signed.
- A copy of the signed PDF for everyone who signed.
What tamper-evident means
A common technique is to link each entry in the log to the one before it with a hash, a short fingerprint calculated from its content. Change, reorder or delete an entry and the fingerprints no longer match, so the change shows. AgreeVia records each view and signature with a server timestamp and chains the history with SHA-256. The same idea applies to the document: change one character of the signed PDF and its fingerprint changes.
That is why we say tamper-evident rather than tamper-proof. Nothing is impossible to alter; the point is that an alteration can't go unnoticed.
What it doesn't prove
- Who the signer really is. A signature made from an emailed link is tied to that email address. AgreeVia doesn't check identity documents, so send the link to an address you know belongs to the right person.
- That they understood it. The trail shows they opened it and signed, not that they read it carefully.
- That the contract is fair or enforceable. A well-evidenced signature on a bad clause is still a bad clause.
- That the document can be signed this way. Wills and some deeds are exceptions (are electronic signatures legal in the UK?).
Will a court accept it?
The law is on your side. Under the Electronic Communications Act 2000 an electronic signature can be presented as evidence on whether a communication is genuine or unaltered (section 7). The Law Commission's 2019 report concluded that an electronic signature is admissible in evidence, and that courts look at all the circumstances to decide whether the signer meant to sign (Law Commission). A court then decides how much weight the evidence deserves. A timestamped, tamper-evident trail from a system that records who was asked, when they opened it and when they signed carries more weight than a pasted image of a signature. If a lot depends on it, a solicitor can say how it would be argued in your case.
How to check one
Anyone can check a finished AgreeVia document at agreevia.co.uk/verify, and the sender can download an evidence package that sets the record out. Keep the signed PDF and the evidence together for as long as you might need them (how long to keep contracts and invoices).
Questions people ask
Is a tamper-evident audit trail the same as an advanced electronic signature?
No. An advanced electronic signature is a particular kind of signature with stricter technical requirements, which some documents need. An audit trail is the record around a signature. AgreeVia records simple electronic signatures with an audit trail.
Can anyone check a signed document?
Yes. Anyone with the document can check it at agreevia.co.uk/verify.
What should I keep?
The signed PDF and the evidence package or audit trail, for as long as a claim could still be brought.
This guide explains the general position in the UK as we understand it on 25 October 2026. The law differs between England and Wales, Scotland and Northern Ireland, and it changes. If something important turns on it, talk to a solicitor or an accountant.
Templates and tools for this
Send your first agreement free
Send a document your client signs from a link, with a tamper-evident record of every view and signature.
Free for 3 documents a month, no card needed. AgreeVia works in your browser and is live on Google Play. Coming soon to the App Store.