Thornfield Engineering Services' commercial director pitched a 15% revenue growth plan to the board. The finance director ran the numbers through the three-statement model and found that, at the current debtor days of 72 and with the required capex to support delivery, the plan consumed £8.3m of additional cash in year one — cash the business did not have. The board approved a phased 9% plan instead, preserving covenant headroom and avoiding a premature equity raise. Linking the sales plan to the financial model before the board meeting is the difference between a credible growth strategy and an aspirational guess.
Three-Statement Model
An integrated financial model in which the income statement, balance sheet and cash flow statement are dynamically linked. Revenue and margin assumptions drive the P&L; working-capital ratios (DSO, DIO, DPO) translate into balance-sheet movements; and the cash flow statement reconciles operating profit to net cash, incorporating capex and financing. Any change in a commercial assumption — price, volume, payment terms — flows automatically through all three statements.
Cash Cost of Growth
The additional cash absorbed by working capital and capital investment when a business grows its revenue. Calculated as the incremental working-capital requirement (driven by DSO and DIO) plus growth-enabling capex, minus any additional trade payables (DPO leverage). A business with 70-day DSO and 15% gross margin can absorb far less growth from internal cash generation than a business with 30-day DSO and 40% gross margin.
For UK engineering services firms, the primary working-capital driver is accrued revenue — work performed but not yet invoiced or collected. A 10% revenue growth with 72-day DSO requires approximately £2.9m of additional receivables financing per £20m of new revenue. Understanding this mechanic is essential before committing to a customer or contract.
Covenant stress-testing requires modelling the downside case through to the covenant metric — typically net debt/EBITDA or interest cover — for each quarter of the plan horizon. UK banks expect this analysis at annual review; presenting it proactively, with remediation steps already modelled, is a mark of commercial financial maturity.
| Scenario | Revenue growth | Net debt/EBITDA (year-end) | DSCR (year 1) |
|---|---|---|---|
| Base case | +15% | 2.9x | 1.28x |
| Conservative | +9% | 2.3x | 1.47x |
| Downside (margin compression) | +9%, -2pp margin | 2.6x | 1.19x |
| Stress (macro slowdown) | +3% | 3.1x — covenant breach | 0.98x — covenant breach |
After adopting the conservative 9% plan, Thornfield's commercial finance team builds a monthly rolling model with automatic covenant recalculation. When a key contract is delayed by eight weeks in Q2, the model flags a potential DSCR breach in Q3. The finance director pre-emptively arranges a six-week covenant holiday with NatWest, avoiding a technical default. The model — not the delay — becomes the board's most valued commercial management tool.
⚠️Building the sales plan without a linked financial model
→ Any revenue growth target that is not modelled through working capital, capex and cash flow is an aspiration, not a plan. Build the three-statement linkage before seeking board approval — the cash cost of growth almost always surprises senior commercial managers.
⚠️Using EBITDA as a proxy for cash generation in a growth phase
→ EBITDA excludes working-capital movements — the exact component that consumes cash during growth. Use operating cash flow (EBITDA minus capex minus working-capital absorption) as the primary financial planning metric.
⚠️Presenting only the base case to the bank
→ Present base, conservative and stress cases to your bank proactively. Banks using internal models assume stress scenarios anyway — pre-empting with your own quantified downside demonstrates financial rigour and reduces perceived credit risk.