A busy law firm can appear profitable while still facing significant cash-flow pressures. Fee earners may be fully occupied and new instructions may be arriving, but if work remains unbilled or invoices unpaid, that income is not yet available to fund recruitment, technology or expansion.
This delay is known as law firm lock up.
Law firm lock up measures how long it takes for work to turn into cash. It includes both work in progress (WIP) that hasn’t yet been billed and invoices that are still waiting to be paid.
According to the latest Law Society Financial Benchmarking Survey, the total lock up across participating UK firms has fallen to 134 days, compared to 146 in 2024. While that’s encouraging to hear, it still means many firms are waiting more than four months before they receive payment for work they’ve already completed.
During that time, firms still need to pay VAT returns, salaries and other operational business costs, despite much of that revenue remaining tied up in WIP.
For firms looking to grow, that delay matters. But specialist law firm finance can help firms mitigate the impact of lock up and retain cash within the business for wider plans.
The reality of billing delays in the legal sector
Long lock up periods are an operational reality across the legal sector:
- A property transaction may take months to complete.
- Litigation follows court timetables that aren’t always consistent.
- Larger legal matters are often billed in stages rather than as one lump sum.
- Client approval processes can delay payment after an invoice is raised.
While law firms find themselves waiting for cash to become available, day-to-day practice operations don’t stop, as Managing Partners and Finance Directors continue to manage staffing costs, equipment and regular HMRC payments.
For growing firms, the speed at which revenue becomes available cash is a challenge.
Why law firm lock up is holding back your firm’s growth plans
Firms often need to invest in growth before a return on investment is made, whether that’s hiring new talent, upgrading case management software, or expanding practice areas.
All these plans require upfront investment today, for additional income to follow later.
When law firm lock up is high, these decisions become harder.
Firms may postpone recruitment plans despite having more work than their capacity allows. Technology investments to improve efficiency are pushed back because cash is still sitting in WIP and is yet to be invoiced. Some firms rely on overdrafts or cash reserves to bridge the gap between work being completed and payment being made.
When cash reserves are stretched, it becomes harder to commit to growth plans, even when your practice needs them.
For smaller firms in particular, these delays can have a lasting impact. Waiting six months to recruit the right person or invest in better systems can slow growth long after the cash eventually arrives.
How to improve lock up period in a law firm and make cash available
If you’re looking at how to improve the lock up period in a law firm, financial discipline should always come first. Practical steps include:
- Review WIP regularly
- Agree billing milestones early
- Raise invoices promptly
- Ensure payment terms are clear
- Forecast unavoidable timing gaps
Making small improvements consistently often has a bigger impact than carrying out one large process change. But they don’t always solve the immediate challenge of cash flow gaps and growth investment. Sometimes an opportunity can’t wait for invoices to be paid.
That’s where specialist law firm funding can be a useful option. Instead of waiting for every matter to complete, firms can access working capital that’s already sitting within the business. That gives partners more freedom to recruit, invest and expand without disrupting client relationships.
Many firms also review their wider law firm cash flow alongside funding options. Looking at billing processes, collections and funding together usually creates a stronger long term result than tackling each issue separately.
If you’re exploring broader legal finance options, funding should support your plans rather than dictate them. The aim is simple: give the business the confidence to move when the right opportunity arrives.
Summary
Law firm lock up, without careful planning, can affect recruitment, investment and other growth plans for legal practices.
It even impacts the confidence to take on larger opportunities.
Healthy profits don’t always equate to healthy cash flow, as money can often remain tied up in work that’s still progressing or waiting to be paid.
Understanding lock up and factoring potential delays into your cash flow planning can support more proactive financial management. Mapping out regular payments throughout the year and using law firm finance to support when cash flow gaps may occur, can enable firms to keep growth moving in the right direction, without delayed revenue holding them back.
Looking for more practical advice on how to grow a law firm? Explore our insights on funding and sustainable growth for ambitious legal practices.