very debatable area but have a read of whats below and have a look through the site.

be aware vosa are changing their minds frequently

taken from: http://www.dft.gov.uk/stellent/group...ut_026293.hcsp

A worker is anyone who provides work or services under a contract, express or implied. A mobile worker is any worker forming part of the travelling staff (typically drivers and crew, but also trainees and apprentices) who is in the service of an undertaking which operates road transport services for passengers or the movement of goods. Mobile workers include drivers who work for hire and reward companies or companies with own account operations.

Typically, this means

drivers of vehicles with a tachograph in them (unless they have an exemption from 3820/85/EC), i.e. goods vehicles over 3.5 tonnes, coaches and inter-urban bus services,
members of the vehicle crew and
any others who form part of the travelling staff.
A number of road transport operations require attendants who must accompany the driver by law, or fulfil a function ancillary to driving (e.g. navigating or crew to accompany abnormal loads), or security staff for high value goods. Travelling staff may include a range of individuals such as porters in household removals; draymen in brewery deliveries movements, conductors on inter-urban buses. These would all be covered by the Regulations.
The Regulations do not apply to:

Mobile workers who are not participating in road transport activities covered by Community Drivers' Hours regulation or in some cases the AETR (e.g. employed taxi drivers, certain van drivers, chauffeurs)
Any drivers, crew, travelling staff who do not come within the definition of "mobile workers" in the RTD (e.g. a teacher who drives a PSV on a school trip, that is subject to the Community rules)
Passengers (e.g. construction workers being ferried to a building site would be passengers rather than travelling staff)
Self-employed drivers (see Section 1.4)
any worker who only occasionally does work which is within the scope of Community Drivers' Hours regulation - 3820/85/EEC (see Section 1.3)