The Hidden VAT Trap in the Consultant Model: And How to Fix It

The consultant model is one of the fastest-growing segments of the UK legal market. Firms like Setfords, Keystone Law, Taylor Rose, and Spencer West have built their entire business around it. But behind the headline numbers; hundreds of new recruits, significant revenue growth; there's a quieter story: a growing number of small and medium firms are taking on their first consultants, attracted by the model's low overhead and flexibility.

These firms aren't in the same league as the big fee-share players. They're 5-20 fee earner firms taking on one or two self-employed consultants, usually a senior solicitor who wants to go independent but doesn't want to set up their own SRA-regulated practice. The arrangement is simple: the consultant uses the firm's SRA authorisation, supervision, and infrastructure, and in return gives the firm 20-30% of their billed profit costs. The consultant keeps 70-80%.

It's a good deal for both sides. But most firms running it for the first time are sitting on a hidden VAT cash flow trap that nobody warned them about. And it's quietly costing them thousands.

How the consultant model works financially

The financial mechanics of a consultant arrangement are straightforward:

The consultant does the legal work under the firm's SRA authorisation
The firm raises an invoice to the lay client; including profit costs, disbursements, and VAT
The client pays the firm
The consultant invoices the firm for their share of the profit costs (typically 70-80%), plus VAT
The firm pays the consultant
The firm retains its 20-30% share

Steps 1-3 are the firm's revenue. Steps 4-5 are the firm's cost. Step 6 is the firm's margin. Simple enough on paper.

But look at the VAT mechanics, and the problem appears.

The VAT timing gap

Here's what happens under standard (accrual) VAT accounting; which is what most firms of this size use:

When the firm raises the client invoice (step 2), output VAT becomes due. Under UK VAT rules (VAT Notice 700, section 14), the tax point; the date on which VAT becomes due; is the date the invoice is issued (or the date payment is received, whichever is earlier). So if the firm raises a £10,000 invoice + £2,000 VAT on 1 March, the £2,000 output VAT is due in the VAT period covering 1 March.

The firm can only reclaim input VAT on the consultant's fee when it receives a valid VAT invoice from the consultant (step 4). Under VAT Notice 700, section 10, input tax is reclaimable in the VAT period in which the tax point for the supply falls; which is when the consultant issues their invoice (or when the firm pays, whichever is earlier).

But here's the problem: in most consultant arrangements, the consultant doesn't invoice the firm until the client pays. This is the standard arrangement; and it makes sense. The consultant doesn't want to invoice the firm for money the firm hasn't received yet. So the consultant waits until the client pays (step 3), then sends their invoice (step 4).

If the client takes three months to pay, the consultant's invoice; and the input VAT reclaim; falls in a different VAT period than the client invoice. The firm has already paid (or accrued) the output VAT to HMRC, but can't yet reclaim the input VAT on the consultant's fee.

What that costs in practice

Consider a typical consultant matter. The firm raises an invoice for £10,000 + £2,000 VAT. The consultant's share is 75% of profit costs; £7,500 + £1,500 VAT.

If the client invoice is raised on 1 March (Q1 VAT period, ending 31 March), the firm owes £2,000 in output VAT for that period.

If the client pays on 15 May (Q2 VAT period, ending 30 June), the consultant sends their invoice to the firm on 20 May. The firm can now reclaim £1,500 in input VAT; but in the Q2 VAT period, not Q1.

In Q1, the firm pays HMRC the full £2,000 output VAT with no offset. In Q2, the firm reclaims £1,500 input VAT. The net position over both periods is correct; £500 net VAT (the firm's retained share of profit costs × 20%). But the firm has carried £1,500 of VAT as a cash flow burden for an entire quarter.

Now scale that across 20 active consultant matters, each with an average client invoice of £8,000 and an average payment delay of 60 days. That's £24,000 of VAT sitting in the gap at any given time; money the firm is funding out of its own cash flow while waiting for the consultant's invoice to arrive.

For a small firm operating on tight margins, that's a material cash flow problem. And it's entirely hidden; most firms don't even realise it's happening until their accountant points out that their VAT bill is consistently higher than expected in quarters with high consultant billing.

The fix: simultaneous invoicing

The solution is structurally simple: raise the consultant's invoice at the same time as the client invoice. If both invoices are issued in the same VAT period, the output VAT and input VAT offset each other immediately. No gap. No cash flow burden. No funding HMRC with the firm's money while waiting for the consultant to send their bill.

This is where self-billing comes in. Under a self-billing arrangement, the firm (as the buyer of the consultant's services) issues the VAT invoice on behalf of the consultant (the supplier). The firm controls the timing. So instead of waiting for the consultant to send their invoice after the client pays, the firm generates the consultant's self-billing invoice at the moment the client invoice is raised.

Both invoices are dated the same day. Both tax points fall in the same VAT period. The output VAT on the client invoice and the input VAT on the consultant's self-billing invoice are recorded in the same VAT return. The firm's net VAT liability reflects only its retained share; not the full client invoice amount.

Self-billing is a well-established VAT mechanism. HMRC requires a self-billing agreement between the parties, and the consultant must be VAT-registered and have agreed to the arrangement. But once set up, it eliminates the timing gap entirely.

How OrdoLux handles this

OrdoLux's Consultant Invoicing module was built specifically to solve this problem. Here's how it works:

1. Fee splits are configured per matter. Each consultant has a default split percentage (e.g., 75%), which can be overridden at the matter level. Multiple fee earners can be on the same matter; consultant + host firm, consultant + referral fee earner, two consultants splitting between them, supervising solicitor allocations. Each person's percentage is transparent, and the splits must total 100%.

2. When the firm raises a client invoice, OrdoLux automatically generates a self-billing invoice for each consultant on that matter. Not the next day. Not when the client pays. At the same time. The self-billing invoice is calculated at the consultant's agreed percentage of profit costs, with VAT applied at the consultant's VAT rate, and is correctly referenced back to the client invoice.

3. Both invoices are VAT-compliant and dated the same day. The output VAT on the client invoice and the input VAT on the consultant's self-billing invoice fall in the same VAT period. The firm's net VAT liability reflects only its retained share. No gap. No cash flow burden.

4. The self-billing invoices sync to Xero or QuickBooks Online as bills. No manual entry. When the consultant is paid, the status updates automatically in OrdoLux. The accountant sees everything in their system; the fee earner sees everything in OrdoLux. No double entry, no reconciliation nightmare.

5. Each consultant has their own dashboard. They can see their matters, their invoices, their outstanding balance, and their account history. They don't see the firm's other consultants or the firm's financials. Role-based visibility keeps everything clean.

6. Multiple invoicing entities are supported. If a consultant operates through a personal service company, OrdoLux captures the correct invoicing entity, address, company registration number, and VAT number. The self-billing invoice is issued to the right entity, not to the individual.

Why this matters for firms growing into the consultant model

The big fee-share firms; Setfords, Keystone, Spencer West; have built proprietary systems to handle this. They've invested heavily in the infrastructure because it's core to their business model. They don't have the VAT gap because their systems generate consultant invoices in real time.

Small and medium firms taking on their first consultants don't have that infrastructure. They're running on traditional practice management software that assumes every fee earner is an employee, every invoice goes to one account, and billing flows in one direction. The consultant model breaks all of those assumptions; and firms end up bridging the gaps with spreadsheets, manual bills, and month-end reconciliation that doesn't scale.

The result is the VAT gap described above. It's not a theoretical problem; it's a real, quantifiable cash flow burden that hits firms in their VAT returns, quarter after quarter. And most firms don't even know it's there until someone traces the cash flow and finds the gap.

OrdoLux closes that gap. Not with a workaround or a spreadsheet template; with a purpose-built module that handles the consultant billing cycle end to end: fee split configuration, simultaneous self-billing invoice generation, VAT compliance, accounting sync, and consultant self-service.

If you're taking on consultants for the first time; or if you're already running the model and your VAT bill keeps surprising you; it's worth asking whether your current system is handling this. Because if it isn't, you're funding HMRC's VAT gap with your own cash flow. And that's a problem that only gets bigger as you take on more consultants.

This article explains the VAT mechanics of the consultant fee-sharing model based on publicly available HMRC guidance (VAT Notice 700). It is not legal or tax advice. Firms should consult their accountant or tax adviser to understand how these rules apply to their specific circumstances. Self-billing arrangements require agreement between the parties and compliance with HMRC's self-billing conditions. OrdoLux is a case management platform, not a tax adviser.