Inspection, Defects and Reporting
Minor versus major
A minor defect is one that does not make the vehicle unsafe to drive but must be fixed soon - a blown marker lamp, a worn wiper blade, a cracked mirror. A major defect affects safety or emissions and grounds the vehicle until it is repaired: faulty brakes, a broken spring, a cracked wheel, steering play, a leaking air line, an insecure load.
What you must do
If you find a defect, you must not drive a vehicle that is unsafe. Report it to the operator, and where your system requires it, record it in writing. Under the national heavy vehicle rules the operator must keep records and act on defects, and the driver must not drive a vehicle that has been grounded or that they know is defective.
Authorised officers can issue defect notices. An official caution records a minor issue; a minor defect notice requires repair and, usually, self-clearance within a set period; a major defect notice grounds the vehicle and requires inspection before it may be used again. Ignoring a notice and driving anyway is a serious offence.
Routine inspection
Between formal services you are the inspector. Watch for brake drag, air pressure loss overnight, uneven tyre wear (which signals alignment or load problems), oil and coolant loss, and anything that feels different through the wheel or the seat. A driver who reports early prevents a roadside grounding later.
Worked example: during a pre-start you find one rear inner dual tyre flat. That is not a minor defect - running on the outer tyre overloads it and can cause a blowout. The vehicle stays parked, the operator is notified, and the wheel is changed before the trip begins, even if it makes the delivery late.