Law firm practice management software in London: custom build or licence in 2026?

The verdict in three sentences

For a 35-lawyer firm in London, an off-the-shelf licence remains the right choice as long as your processes look like your peers': it costs EUR 25,000 to 63,000 a year and goes live in 6 to 10 weeks. A custom build (EUR 70,000 to 130,000, then about EUR 1,000 a month) pays off when your fixed-fee billing, conflict rules or client reporting do not fit a packaged product. In both cases, legal professional privilege requires UK or EU hosting, strong encryption and a full access audit trail.

What each option really costs over five years

The per-user price often hides paid modules (e-signature, client portal, accounting connector) and annual price increases, usually 3 to 7 %. Here is a 2026 order of magnitude for 35 lawyers and 12 support staff.

The tipping point sits around EUR 90 to 110 per user per month: below it, the licence is almost always cheaper over five years; above it, the custom build pays back between year three and year four.

The features that matter in a commercial firm

A commercial firm is not judged by its shared calendar but by the quality of its time recording and billing. The gaps between tools come down to six features.

The most underestimated topic is the realisation rate: a firm that loses 8 % of its billable time because entry is clumsy leaves tens of thousands of euros on the table every year, whatever the tool.

Privilege and hosting: the checklist

Before signing, get in writing: UK or EU hosting, encryption at rest and in transit, two-factor authentication for every account, access logs kept for at least one year, full data reversibility (readable export within 30 days) and an audit clause. A vendor that refuses the reversibility clause locks you in; a custom developer that does not assign the code rights does too.

Mini case study

James, managing partner of a 35-lawyer commercial firm in the City of London, pays a licence at EUR 110 per user per month for 47 accounts: EUR 62,040 a year, or EUR 310,200 over five years. A custom tool quoted at EUR 105,000 plus EUR 12,000 of annual maintenance costs EUR 165,000 over five years. The net licence saving reaches EUR 50,040 a year. If he also recovers 150 lost billable hours over the year (0.3 % of the 49,000 hours billed by his 35 lawyers, average rate EUR 320), he gains a further EUR 48,000. With about EUR 98,000 of annual gain, the investment pays back in roughly 13 months, provided partners enforce daily time entry.

FAQ

How long does it take to build a custom practice management tool?

Allow 4 to 6 months for a first version covering time, conflicts, billing and reporting. A reduced first release (time and billing) can ship in 10 to 12 weeks.

Does an off-the-shelf licence protect privilege?

Major vendors offer UK or EU hosting and compliant encryption, but check your plan: some entry-level tiers at EUR 60 a month host outside the region. Ask for the exact location of servers and backups.

Can we migrate 10 years of matter history?

Yes, migration usually costs EUR 8,000 to 20,000 depending on data quality. Plan 2 to 4 weeks of prior clean-up of client records and duplicates.

Is a custom build suitable for a firm under 15 lawyers?

Rarely: at 15 users, a EUR 90 licence costs about EUR 16,000 a year, which makes a EUR 70,000 build hard to recover. Custom mostly makes sense above 30 users or for unusual billing models.

Who maintains the custom tool after delivery?

A maintenance contract at about EUR 1,000 a month covers fixes, security updates and 1 to 2 days of enhancements. You own the code, so you can switch providers.

Let's scope your project. We price your practice management tool (time recording, conflicts, billing, compliant hosting) with an indicative budget and a phased plan. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.