Britain's best new building: can a tiny dairy farm beat the epic Elizabeth line?

It is like trying to compare a Hollywood blockbuster with an indie documentary. In this year's RIBA Stirling prize for the best building in the country, the £19bn Elizabeth line and the 67-acre regeneration of King's Cross in London go head to head with a little row of council houses and a refurbished farmyard in Dorset.

- Oliver Wainwright

The architecture prize is always a case of apples and oranges, but the disparity in scale and cost has never been more extreme than on this year's shortlist. Joining the diverse bunch are also two complex transformations of existing buildings, the Victorian National Portrait Gallery and the postwar Park Hill housing estate in Sheffield.

Of the two big beasts, the Elizabeth line might clinch it. It is the one bit of UK transport infrastructure that makes you feel like you are living in the 21st century, a bright, spacious world of airy tunnels and sleek sliding doors. It is the part below ground that's up for the prize, namely the "line-wide" design by Grimshaw architects and Atkins engineers, who have created a streamlined universe of white concrete panelling that gives travellers the feeling they are walking the sci-fi corridors of Stanley Kubrick's spaceship in 2001: A Space Odyssey.If there is a complaint, it is that all the stations are alike. The Lizzie line is an efficient wonder, but it is also a blur of beige.