Mired in economic crisis, Spain is to vote for change in a general election on Sunday with polls indicating that two new parties who have pledged reform entering parliament.
Prime Minister Mariano Rajoy's conservative Popular Party is tipped to win the largest share of the vote, taking 25-30 percent, but lose its absolute majority, in a move likely to make formation of a stable government difficult.
The Popular Party and the Socialists have alternated in power since 1982.
But with two new parties in the running -- far-left Podemos and centre-right Ciudadanos, both of whom are expected to secure more than 15 percent -- the rules of the game have changed.
"This is a change like we have never had before because we are experiencing a political, economic and institutional crisis like we have never known, with corruption scandals hitting everyone from the monarchy down to the village town halls," said political science professor Pablo Simon of Madrid's Carlos III University.
The global credit crunch of 2008 plunged Spain into a deep economic crisis which forced the Socialist government in power at the time to impose steep spending cuts.
The austerity drive continued after the Popular Party swept to power in a landslide in November 2011, with healthcare and education spending especially hard hit.
The unemployment rate soared to record high of 27 percent at the beginning of 2013 and tens of thousands of people lost their homes because they were unable to pay their mortgages.
Massive street protests began in 2011 and led to the emergence last year of Podemos, an anti-austerity party set up by Pablo Iglesias, a pony-tailed university professor in his late 30s.
The party, which rails against inequality and corruption, has stolen votes away from the Socialists, who are still tainted in the eyes of many voters because of the way they handled the start of the crisis.
At the start of the year, Podemos soared to the top of opinion polls with as much as 28 percent support. Although its support fell, it has surged again on the eve of the election.
Like Podemos, business-friendly Ciudadanos --which until last year was only a small regional party that competed for votes only in the northeastern region of Catalonia -- has vowed to fight corruption.
Ciudadanos, which backs a labour market reform and greater investments in research and development to boost job creation, has drawn voters from the left and right.
Although Spain, with its population of 47 million, emerged from five years of on-off recession in the second half of 2013, its unemployment rate still surpasses 21 percent -- the highest in the EU after Greece.
Rajoy has presented himself as the guarantor of the economic recovery and national unity, in the face of a separatist challenge in Catalonia.
His campaign has focused on older voters. Of Spain's 35.6 million eligible voters, 10.9 million are over 60 years old.
"In democracy, it is the party which gets the most votes who should govern," he has said repeatedly during the campaign.
If it loses its absolute majority, as polls suggest, the Popular Party will need the support of at least one other large party.
Podemos is out of the question and the main opposition Socialists, led by Pedro Sanchez, would be an unlikely bedfellow.
While there is much overlap between the Popular Party and Ciudadanos in terms of economic policy, Ciudadanos leader Albert Rivera has said he will back neither Rajoy nor Sanchez for the role of prime minister.
His words have been interpreted as a sign that Ciudadanos could back a Popular Party government if it is led by someone other than the Rajoy, with his deputy, Soraya Saenz de Santamaria, frequently cited as the most promising candidate.
On the left, the Socialists could ally themselves with Podemos but polls suggest that they would still fall short of an absolute majority of 176 seats in the 350-seat assembly.
Within business circles "there is a great deal of concern over the political instability that could emerge in Spain" after the elections, said Ricardo Mur, head of an IT firm based in the northeastern city of Zaragoza.