How the market prices the work
Most reputable UK and European providers quote a set fee per operator-shift or per day, sized from four inputs: location, total area of concern, the number of separate rooms, and the technical density of those rooms — conferencing kit, IT infrastructure, vehicles. A focused sweep of a boardroom and a handful of executive offices is typically a one-day, two-operator engagement; a floor or a multi-site programme scales in shifts from there.
Expect UK single-day corporate engagements to land in the low-to-mid four figures, with complex or multi-day work quoted per project. Some providers publish per-square-foot rates imported from the US model, but shift pricing dominates because sweep time is driven by room count and technical density far more than by floor area.
What actually drives the number
Five factors move every quote. Scope: the number of rooms and vehicles, not headline floor area. Technical density: every conferencing system, phone, and cable run is inspection time. Threat level: a live-leak investigation or state-linked concern demands deeper method and senior operators. Scheduling: discreet out-of-hours and weekend work — which most corporate sweeps should be — carries a premium. And reporting: a findings report you can put in front of an audit committee or a court takes qualified time to write.
Recurring programmes price better per sweep than one-offs: the provider amortises familiarisation, keeps your baseline RF environment on file, and can schedule efficiently. If you expect to sweep more than twice a year, ask for programme pricing rather than repeated ad-hoc quotes.
Where cheap sweeps cut corners
The equipment gap is real: professional spectrum analysis, non-linear junction detection and thermal inspection represent a six-figure equipment investment that a low-cost operator does not have. A £500 or $500 "sweep" is generally a handheld RF detector walk-through — capable of missing anything dormant, burst-transmitting, hard-wired, or optical, which is to say most of the professional threat.
The honest budgeting comparison is not sweep versus no sweep; it is sweep cost versus the value of the information discussed in the room and the cost of its loss. Framed that way, a proportionate programme for a company doing material deals is one of the cheaper controls in the security budget — and one of the very few that also generates legal evidence of diligence.