Sánchez's biggest critic: First lady Begoña Gómez

And although Sánchez, as a leading politician, is used to criticism – and will have to get used to even more now he is president with the smallest minority government in Spain's democratic history – the harshest and most regular of this criticism comes from Begoña, a charismatic, positive woman whose drive and energy give her husband confidence and determination, and also keep him grounded.

The couple has two daughters, Carlota, 13 and Ainhoa, 11 – the latter being a popular Basque name as a nod to Begoña's Bilbao roots – and lives in the Greater Madrid region's 'footballer and celebrity' belt, Pozuelo de Alarcón, officially Spain's wealthiest town.

Madrid-born Pedro and his wife, who grew up in the centre-northern province of León, have always tried to encourage the same enthusiasm in their girls as they themselves share for reading and sports – Pedro is an accomplished basketball player – and, whenever they can, the couple likes to go to pop and rock concerts.

Among their favourite artists are the Spanish group La Habitación Roja ('The Red Room') and off-the-wall Icelandic indie-pop singer-songwriter Björk.

The family would really have preferred to carry on living in their beloved long-term home in Pozuelo de Alarcón, but Sánchez's demanding new role means they will have to move into the Moncloa Palace, the official presidential residence, and remain there until at least the end of 2019 when the next general elections are due.

Pedro says his wife and two daughters are his support network and have been his rock during his turbulent, rollercoaster political career – which saw him within inches of becoming president in 2016 and then leaving the party and his post altogether months later, only to come full circle and take up his place in the Moncloa two years after its door was slammed in his face as he was about to cross the threshold.

But until celebrity magazine Diez Minutos tweeted a photo of Begoña and Pedro on a beach in Ibiza in August 2016, nobody but the former's closest friends and family knew who her husband was.

During an interview on a TV chat show, she admitted that a customer had said to her out of the blue: “Don't tell me you're Pedro Sánchez's wife!”

Begoña, who has a degree in marketing, works for a company which seeks to attract funds for various charities.