Under the Goods Vehicle (Licensing of Operators) Act, if you run vehicles over 3.5 tonnes gross plated weight you must have a standard operator's licence for each Traffic Area in which you have a base. If you are going to be undertaking overseas work then you will need an international licence. Licences are issued by the Driver and Vehicle Standards Agency (DVSA) on behalf of the Traffic Commissioner for that area.
There are several Traffic Areas covering England, Wales and Scotland. In Northern Ireland you must obtain a goods vehicle operator's licence. These licences are issued by the Transport Regulation Unit (TRU) of the Department for Infrastructure.
You can find out more about goods vehicle operator licensing on the Gov.uk and NI Direct websites.
It is an offence to drive, or to permit another person to drive a vehicle on the road without a valid driving licence which covers that category of vehicle. To obtain a licence, drivers must take and pass a driving test for the appropriate class of vehicle. To drive a vehicle that exceeds 7.5 tonnes gross weight a driver must hold an LGV (large goods vehicle) licence.
Professional lorry drivers also require a certificate of professional competence (CPC).
All vehicles used on the road must have a current vehicle excise duty licence (road tax).
You can find out more about driver licensing, and check current rates of vehicle excise duty, on the Gov.uk and NI Direct websites.