Polls published this week showed Spain's centre-right liberal party Ciudadanos, led by Albert Rivera, in a battle with the governing conservative Popular Party (PP), led by Mariano Rajoy, for first place in Spanish politics.

A GAD3 poll for the newspaper ABC on Sunday showed the PP scraping past Ciudadanos again, but with both on 25% of the vote. In the January version of the same survey, Mr. Rivera's party beat Mr. Rajoy by more than 400,000 projected votes.

In El País on Friday, February's Metroscopia poll also put Ciudadanos in the lead, and for the second month running, this time ...