In the UK if your drone has a camera on it, regardless of the size, you MUST obtain an Operator’s ID and display that clearly on the drone. More information on these rules can be found here: https://www.caa.co.uk/drones/ (opens in new tab)
At minimum we recommend that anyone wishing to operate a drone anywhere for any reason should at least have an A2 Certificate of Competency (A2 CofC).  This can then lead onto the General Visual Line of Sight Certificate (GVC).
The A2 CofC allows you to fly small drones in specific low-risk scenarios and it involves completing an online theory test. The GVC is a more comprehensive certification for those operating in higher-risk environments and requires additional training and an in-person flight assessment.
If you are doing any work commercially, it is UK Law that you have the correct liability insurance.
So in answer to the question – No, you don’t need a ‘license’, but you do need an ‘Operators ID’.