Almost every UK practice that rolls out a client portal sees the same curve. Adoption climbs sharply for the first three months, peaks somewhere between 35 and 45 percent of active clients, and then flatlines. Partners look at the numbers, conclude that "clients just prefer email," and the portal becomes a half-used cost centre. The conclusion is wrong. The plateau is real, but its cause is almost always operational rather than behavioural.
The 40 percent ceiling is a self-inflicted wound
The clients who adopt early are the ones for whom the portal solves a visible problem - sharing large files, signing engagement letters, accessing prior-year returns. Once that segment is converted, adoption stalls because the firm keeps doing everything else by email. If your team still sends document requests, status updates, and ad-hoc questions by personal email, the client correctly concludes that the portal is optional. And optional channels in professional services always lose to the path of least resistance.
The fix is therefore not a clever marketing campaign aimed at clients. It is an internal policy change aimed at staff.
Why clients silently abandon the portal
Three patterns show up repeatedly in adoption data. First, password fatigue - if the portal requires a separate username and password that the client only uses occasionally, they will forget it, fail the reset, and revert to email. Second, mobile experience - if the portal does not work cleanly on a phone, business owners who do their admin in 90-second windows between meetings will give up. Third, mixed signals - if the partner says "use the portal" but the manager replies to a portal message via personal email, the client follows the manager.
The internal policy shift that changes everything
The single most effective intervention is a hard rule: all client communication and document exchange happens in the portal, no exceptions, enforced at the partner level. This is uncomfortable for two months and transformative thereafter.
- Outbound emails to clients are limited to portal notifications - no document attachments, no substantive replies
- Inbound client emails are answered with a one-line response: "Replying via the portal so we keep your data secure - link here"
- Document requests are issued only through the portal request feature, never as email attachments
- Engagement letters and authority forms are sent for e-signature in the portal, not as PDF attachments
- Internal performance is measured on portal-message ratio, not just email response time
Magic links are not a gimmick
The biggest single technical lever is access friction. Passwordless or magic-link access - where the client receives a one-tap login link to their registered email - typically lifts adoption by 15 to 25 percentage points on its own. The reason is mundane: clients who only log in twice a month will never remember a password, and every password reset is a chance to give up.
If your current portal still demands traditional credentials with no fallback, that is the first thing to fix. If it offers magic links, make sure they are turned on by default for every new client during onboarding.
Branding matters more than partners think
A portal that looks like a generic SaaS tool with someone else's logo at the top quietly tells the client they are dealing with a third party, not their firm. Adoption is materially higher when the portal carries the firm's own brand, domain and colour scheme. This is not vanity - it is trust. Clients log into a branded portal because it feels like their accountant's office. They hesitate on a generic one because it feels like a vendor.
Measure adoption properly or you will measure the wrong thing
"Adoption" is a slippery term. A client who logged in once to sign an engagement letter is not adopted. A useful definition: a client is "actively adopted" if they have logged in at least twice in the last 60 days and have at least one inbound message or document upload in that window. Run this measurement monthly, segment by partner and by client size, and you will see exactly where the gaps are.
Firms that measure adoption this way typically discover that the problem is concentrated in one or two staff members who never enforce the policy, not in the client base as a whole. Fix the staff behaviour and the numbers move within a quarter.
What good looks like
A firm that has broken the 40 percent ceiling typically sits at 75 to 85 percent active adoption within nine months of the policy shift. Email volume to and from clients drops by 60 to 70 percent. Average response time on substantive client queries improves by roughly a third because messages are visible to multiple team members rather than buried in one inbox. AML and GDPR audit posture improves measurably because everything is now in one auditable channel.
Where the practice management layer fits
The portal cannot live in isolation from the rest of the firm. Messages, documents and signatures need to land against the client record alongside jobs, deadlines and compliance status. Accupe provides the practice-management layer where the branded client portal, encrypted messaging, e-signatures and secure file exchange are part of the same workflow your team already uses for capacity, jobs and compliance - so adoption is not a separate initiative, it is just how the firm operates.
Closing
The 40 percent plateau is not a ceiling on what clients will accept. It is a ceiling on how seriously the firm is enforcing the channel. Fix the policy, fix the friction, brand the experience, measure adoption properly, and the ceiling disappears. The firms that have done this are the same ones quietly winning the retention and pricing arguments over the next decade.