Yes. Under Section 7 of the Electronic Communications Act 2000 and Article 25 of the UK eIDAS Regulation, an electronic signature cannot be denied legal effect solely because it exists in electronic form. That covers engagement letters.
But knowing it’s valid is only part of the answer. You also need to know what exactly counts as an e-signature on an engagement letter, which tier the law requires, and how to make sure your setup holds up if a client disputes the engagement later.
That’s what this guide covers.
What Counts as an E-Signature on an Engagement Letter?
Under Article 3 of the UK eIDAS Regulation, an electronic signature is data in electronic form which is attached to or logically associated with other data in electronic form and which is used by the signatory to sign.
Section 7(2) of the Electronic Communications Act 2000 puts it similarly:
anything in electronic form that is incorporated into or logically associated with an electronic communication, and purports to be used by the individual creating it to sign.
In practice, that covers more than most practitioners assume:
- A typed name at the bottom of a document
- A drawn signature on a touchscreen
- A signature captured through a dedicated platform
- A scanned signature image embedded into the document
All fall within the definition, provided the signature is connected to the document and applied with the intention of signing.
The method matters less than two things: whether the signature is logically associated with the specific engagement letter, and whether it was used with the intention of authenticating that document.
Are E-Signatures on an Engagement Letters Valid?
Yes. Under Article 25(1) of the UK eIDAS Regulation, an electronic signature cannot be denied legal effect or admissibility as evidence solely on the grounds that it is in electronic form. Section 7(1) of the Electronic Communications Act 2000 goes further: an electronic signature incorporated into or logically associated with an electronic communication is admissible as evidence on questions of authenticity and integrity.
That applies to engagement letters too. They are commercial agreements, and English law imposes no requirement that they carry a handwritten signature. If the signature meets the definition covered in the section above, it is sufficient.
Article 25(2) of UK eIDAS goes further, confirming that a qualified electronic signature carries the same legal effect as a handwritten signature, equivalent to wet ink. That brings us to the question of what the tiers of e-signature actually are, and which one you need for an engagement letter.
Which E-Signature Tier Do You Need for an Engagement Letter?
UK eIDAS recognises three tiers of electronic signature, each carrying a different level of identity assurance. Here is what each one means in practice:
For engagement letters, simple tier is where you start and, in most cases, where you stay.
How to Make Your E-Signature on an Engagement Letter More Defensible
A valid signature and a defensible one are not the same thing. Validity is binary: the conditions are met or they are not. Defensibility is about what you can prove if a client later disputes the engagement, the scope, or the fee.
The signature is only part of the evidence. How it was captured, what surrounds it, and how it is stored determine whether you can actually rely on it.
These are the habits that close the gap:
- Send the document through a dedicated platform so the signature is embedded in the finalised PDF rather than associated loosely with a separate file. A signature image pasted into a Word document and emailed across does not reliably establish the logical association required under Section 7(2) of the Electronic Communications Act 2000
- Send the final agreed version of the engagement letter, not a draft. Signing a document that is subsequently amended creates a validity problem because the signed version no longer reflects the agreed terms
- Get the letter signed before work begins. A signed letter dated after the engagement started creates an evidential gap on when the client actually agreed to the terms
- Retain the signed document and any accompanying evidence of the signing process together in the client file. The signed PDF alone is not enough if authenticity is challenged
- Countersign on behalf of the firm before filing. An unsigned letter on the firm’s side weakens the record of mutual agreement
The tier of signature determines how easy it is to prove the signatory’s identity in a dispute. It does not determine whether the signature is valid. A simple electronic signature on a weak process can be harder to defend than an advanced signature on a well-documented one.
Conclusion
E-signatures are valid for engagement letters in the UK. Section 7 of the Electronic Communications Act 2000 and Article 25 of the UK eIDAS Regulation both establish that an electronic signature cannot be refused legal effect solely because it is not on paper. A simple electronic signature is sufficient for most engagement letters.
When done through a proper signing platform rather than a Word document sent by email, it becomes even stronger, with a clear audit of how, when, and by whom the letter was signed.
We have reviewed and ranked the top 10 e-signature software options for UK accountants, all built to handle engagement letters and beyond. Check it out here: 10 E-Signature Software for Accountants | FigsFlow
Frequently Asked Questions (FAQs)
Yes. Under Section 7 of the Electronic Communications Act 2000 and Article 25 of the UK eIDAS Regulation, an electronic signature cannot be denied legal effect solely because it exists in electronic form. Engagement letters are commercial agreements and carry no requirement for a handwritten signature under English law.
A simple electronic signature is sufficient. Under Article 3 of the UK eIDAS Regulation, this covers a typed name, a drawn signature, or a click through a signing platform. You do not need an advanced or qualified electronic signature for a standard engagement letter.
Three things: a clear intention to authenticate the document, a logical association between the signature and the specific document signed, and sufficient evidence to identify the signatory. These conditions come from Section 7 of the Electronic Communications Act 2000 and Article 25 of UK eIDAS.
Yes. The UK eIDAS Regulation was retained in domestic law through the Electronic Identification and Trust Services for Electronic Transactions (Amendment etc.) (EU Exit) Regulations 2019. The legal framework for electronic signatures remains intact. UK qualified trust services are not automatically recognised as equivalent in the EU, but that does not affect domestic validity.
The burden falls on demonstrating that the signature conditions were met: intent, association with the document, and identification of the signatory. A platform that captures how and when the document was signed strengthens your position. A signature image sent by email with no supporting record is harder to rely on.
