The UK has a wide spread of universities, and English test expectations move with the course rather than the brand alone. That said, some universities and groups are useful reference points when you are shortlisting.
Russell Group universities often specify recognised Indian institutions by name. That makes it especially important to check the exact admission wording if you are applying to places such as University of Birmingham, University of Bristol, University of Leeds, University of Nottingham, University of Southampton, University of Warwick, Durham University, Newcastle University, Queen Mary University of London, or Cardiff University.
For a more open shortlisting approach, many Indian applicants also consider University of Manchester, University of Edinburgh, University of Glasgow, University of Birmingham, University of Leeds, University of Sheffield, University of Sussex, Northumbria University, University of Chester, Coventry University, University of Westminster, and Queen’s University Belfast. The point is not that these all want the same score. The point is that they are common destinations, so you should check each course page rather than relying on hearsay.
If you are applying for business or management, remember that business schools are more likely to have their own rules. If you are applying for engineering, science, or computing, the score can be the same as the university norm or a little tighter depending on the course.