Why nobody can tell you the size of England's corporate communications market

There is no authoritative figure that isolates England's corporate communications market. Official datasets can describe registered businesses, broad industries or occupations, but none measures this exact service, the work of internal teams and software use together. Quoting one of those adjacent totals as the answer would change the population halfway through the calculation.

Why the available classifications fall short

The ONS UK Standard Industrial Classification 2007 includes class 70.21 for public relations and communication activities. That class covers advice and assistance, which is wider than a defined corporate communications supplier market. It does not separately identify an organisation's employees, investor relations, internal communications, public affairs, crisis work, monitoring platforms or communications software.

The ONS UK business activity dataset reports enterprises and local units from an Inter-Departmental Business Register snapshot taken on 14 March 2025. A regional table can help locate units assigned to an industry code. It cannot show which services they sold, what part of turnover came from communications, or whether an English local unit made the buying decision.

The accompanying quality and methodology report, revised on 24 September 2025, says the register covers businesses registered for VAT or PAYE. It also distinguishes enterprises from local units. Those coverage and unit rules matter before any count is used.

Companies House data products provide registered-office, status, filing and SIC fields for companies on the public register. They are useful for resolving a legal entity. They do not verify current trading capacity, client location, service mix or revenue for a particular offer.

Define the measure before collecting records

A defensible study should publish one question. For example: "What cash expenditure did a fixed population of England-operating buyers incur on externally supplied, authorised corporate communications work during a stated accounting period?" That excludes internal labour and software unless the study names them separately.

Create an admission record for each buyer transaction:

• buyer legal entity and English operating site;
• contracted supplier and service boundary;
• invoice period, currency, VAT treatment and charging unit;
• work accepted, excluded or credited;
• whether the job was advice, content production, internal communication, public affairs, PR, monitoring or software;
• source document, evidence owner and verification date.

Keep a second ledger for internal labour and owned systems. Do not add it to supplier revenue. A third supplier frame may count verified legal entities offering the bounded service, but that is a census frame rather than value.

Sampling and reporting rules

Freeze the eligible buyer population before recruitment. Record non-response and missing invoices rather than estimating them silently. Sample weights need a stated frame, strata and uncertainty method. Report England only when the buying unit or service delivery geography meets the published definition, not because a company's registered office is in London.

The final result should state population, period, unit, inclusions, exclusions, achieved sample, missingness and confidence interval. Until those records exist, the correct output is an evidence gap and a study design, not a market-size number.

When a result becomes publishable

Before releasing an estimate, an independent statistical reviewer should reproduce admissions from the frozen source list and reconcile a sample to contracts or invoices. A finance reviewer should test whether pass-through media, software and consultancy costs were counted once. Publish revisions when late records change the result, and retain the earlier version with its reason for replacement. If the achieved sample cannot support the intended England population, narrow the population instead of widening the claim.

Publication remains on hold pending review by named UK statistical, finance and commercial specialists.