Yes you can, although your clients may require that you operate as a legal company or through an Umbrella Company
Sole Trader is a legal entity which has no separate existence from the owner. A sole trader refers to an individual doing business in his or her own name and in which there is only one owner. The person who organised the business pays personal income taxes on the profits made. You need to register as self-employed.
Advantages
Being a sole trader is the simplest way to run a business since it does not involve paying any registration fees, keeping records and accounts is very straightforward, and you get to keep all the profits. You have complete control on how to manage your business.
Disadvantages
Since you have full responsibility of the business, you are personally liable for any debts that your business runs up. This is a risky option for businesses that need a lot of investment. You raise money for the business out of your own assets, this means you put your home or other assets at risk if your business runs into trouble.
Discuss with your Accountant about whether they feel that the Sole Trader option is right for you