Yes, you can ride a Honda XR125 at the age of 16 in England Great Britain, but with certain conditions. To ride a 125cc motorbike in England, you must have at least a provisional motorbike licence. To get a provisional motorbike licence, you must pass the theory and practical motorbike tests. The practical test assesses your motorbike handling and riding skills, and the theory test tests your knowledge of the rules and regulations of the road.
You must also display L-plates on your motorbike to show other road users that you are a learner. You must not carry passengers until you have passed your full motorbike test and have a full Category A motorbike licence.
Additionally, you must wear the appropriate safety gear, including a helmet, eye protection, and appropriate clothing and footwear.