No, ignore the advice that it’s legal. It’s not. Speak to your union.
Collate information about what jobs you do to demonstrate you do the same or very similar role. The requirement in law is for equal pay for jobs of equal worth.
You don’t have to prove you are as good as him. They have to prove it’s not discrimination.
The route is grievance, ACAS, Tribunal if you want to do battle.
Alternatively go to free half hour appointment with a no win no fee solicitor to see whether you can evidence a claim or criminal charges (and yes, breaches of the Equality Act is an offence).
Wow! I am so glad I have never worked with anyone like you.
I guess in a factory where everyone litteralt does exactly the same job it could be seen as discrimination.
In any job I have ever had your value to the company is determined by you previous roles, your experience, your knowledge, your contacts with other suppliers and customers, your ability to deal with suppliers and customers, your project management skills etc etc.
Some jobs are black and white, and pay should be equal. The vast majority aren’t and in those instances your value to the business and what hey are happy to pay you is determined by a whole host of things.
If you don’t think you are being paid what you are worth or what you could get elsewhere it is up to you to raise it and push for more. It doesn’t matter in the slightest what other people are being paid.