The Guardian is a Fleet Street quality UK newspaper. Its Sunday stablemate is The Observer. Originally The Manchester Guardian it has long dropped the city name and become a national title.
Politically The Guardian is left of centre, though usually endorses the Labour Party rather than the Greens or Liberal Democrats, "Guardian reader" is a polite British collective term for intellectual or middle class supporters of the parties of the left and centre left. The Guardian has a reputation for responsible and accurate journalism.
Its only real competitor is the The Independent, as there is no mid-market centre or left of centre national daily and The Mirror as a tabloid is in a very different niche.