A trade mark registration gives the owner the exclusive right to use the trade mark in connection with products and services for which it is registered.
A registration can be considered a warning in that other competitors wishing to adopt your trade mark may be put off.
A registered trade mark can be used easily to take action against potential infringers. Indeed a registration is required in order for Trading Standards or the police to seize goods on your behalf which are potentially infringements.
An advantage of registration is that your rights are clearly defined and can be bought and sold like any other property.