If you have been self employed for a while or are looking to set up a new business then you may decide to set up a limited company. Unlike when being self employed, limited companies must have at least one director. Often people set up limited companies if they want to be able to employ people and to not have to have payments / loans etc against them as an individual.
Running as a limited company often gives your customers a higher level of trust and can make your business look more professional. It can often allow you to deal with bigger companies than you may be able to if you were self employed. But, there are some downsides.
Accounting often becomes harder when it comes to a limited company compared to that of a sole trader. You may have to pay VAT and corporation tax along with employee wages and contributions.
If you are thinking of setting up a limited company be sure to speak to a competent financial advisor or accountant before doing so and ensure that you have all your procedures in place before starting. This will make accounting easier when you do need to start filing returns etc.