You must register with the local government 28 days before putting the food truck on the road. It is free to register your business. You must also pass the certification of Level 2 or Level 3 food safety and hygiene courses. Level 2 authorizes you to prepare and cook food on the mobile dining car; The third level authorizes you to manage employees.
You need liability insurance to cover accidental poisoning or bad driving that causes customers to be injured. There are real liability risks in any catering service. You may need to consult a professional company, because not every insurance company will cover mobile catering service providers.
You must also make a hazard analysis and key point control plan, also known as HACCP plan. The plan shows how you plan to protect your food from chemical, biological and physical contamination.
You must also register a tax account with HMRC. It is very important to study the streets where fast food trucks are forbidden to operate. You must obtain LPG and PAT test certificates.