Saying its the most popular newspaper in the UK today is like talking about the most popular sunscreen in the UK (for January only).
Most popular of nothing is still nothing. Do you think the Dail Fail readership is 50% of the country? 40%? 30? 20? 10? 5?
No, its readership is well below 2% of country. Even the Lib Dems can get more than 2%.