As standards vary from country to country, travel companies don’t have to use the official classifications that are decided by the local tourist authority. Travel companies in the UK can grade the hotels based on their own rating system.
Many people rely heavily on star ratings when booking hotels. However, there’s neither an international system nor defined parameters. What is a four-star hotel in England can differ greatly from a four-star in Turkey or Spain. It’s for this very reason that companies have their own rating system. Check the description of the hotel to ensure it meets with your expectations before confirming the booking.