PAS 128 survey types can be confusing if you’re not working with them day-to-day. This guide breaks down M1, M2, B, C and D in simple terms so project managers, engineers and contractors can choose the right survey level and manage underground utility risk confidently.

PAS 128 sets the standard for underground utility surveys in UK construction. This guide explains what each survey type means, how to interpret confidence levels, and how PAS 128 helps reduce risk on highways and civils projects before you break ground.

GPR surveys can’t see everything — they detect disturbances and metallic objects beneath the surface. Learn why a layered approach gives safer, more accurate results on UK construction sites.