It comes down to how you come here, how long and the nature of the relationship with the employer in the UK and the employer in India.
if you come to the UK and receive pay here, but not in India - then you should be pay all UK taxes. That is right and fair.
But if you came to the UK via a Visa via a 'company' for a temporary stay and you still continue to receive a seperate salary in India aswell - then your employer is meant to do 'tax equalisation' so that you dont pay anymore tax than had you remained in the India and your benefits in India are meant to stay the same, and the cost of that difference falls on your employer, not you. It is the cost of doing business. Without knowing the full scenario - difficult to say what is the ask or scenario.
I have done the expat thing in the Germany and where i received a UK salary(on which I paid UK taxes) and a Germany salary(to basically cover expenses) for which I also paid Germany taxes. In the event that the Germany considered my UK income for Germany taxes also, then that was paid aswell. But i then went through a tax equalisation process so that i did not have to pay "any more tax than had i stayed in the UK" - the costs of the Germany salary and for taxes was totally on my employer ...