"It is inevitable that we will end up joining with Spain," the author of The Year of the Death of Ricardo Reis told the newspaper Diario de Noticias in Lisbon at the weekend.

Saramago, who has lived on the Spanish island of Lanzarote for the past 10 years, said a united Iberian peninsula of some 55 million people would benefit both Portugal and Spain.

"What do we see when we look at the Iberian peninsula?" he asked. "We see an undivided whole made up of different nationalities, some with their own languages, which have lived more or less in peace."

He denied that the Portuguese people, or their culture, would lose out in a union with Spain. "We would not stop speaking Portuguese or writing in our language and, with 10 million people, we could do nothing but gain from such closeness and territorial, administrative and structural integration," he said.

The 1998 Nobel prize winner, who left Portugal in the early 1990s after a row with the then conservative government over his controversial novel The Gospel According to Jesus Christ, denied he was motivated by anger with his home country.

Critics, however, claimed Saramago was giving vent to anti-Portuguese feelings.

"Saramago's vision belongs to the 19th century, not the 21st," former foreign minister and Madrid ambassador Martins da Cruz, told Diario de Noticias yesterday. "It is very easy to hate Portugal from abroad. What is difficult is to defend our interests, and that is what Saramago fails to do."

Any attempt to unite Portugal with Spain would run into considerable opposition. Portuguese commentators already complain loudly whenever major Spanish banks and companies buy up Portuguese counterparts.

The two countries also row over water, with Portugal complaining that too much is taken out of shared major rivers such as the Tagus and the Douro by the Spaniards.

A poll carried out three years ago found the Portuguese considered the second most important date in their history to be the day in 1640 when they regained independence from Spain. Only the 1974 Carnation Revolution, ending a 40-year rightwing dictatorship, beat it.

Saramago is not the only so-called "iberista" in Portugal, however. A poll in the Sol weekly newspaper earlier this year revealed that 28% of his countrymen were in favour of union with Spain.

A similar poll in Spain's Tiempo magazine found 45% of Spaniards would approve of union - as long as Madrid was the capital and republican Portugal could be persuaded to take on Spain's royal family.

Saramago confirmed his own union with Spain yesterday, marrying Spanish journalist Pilar del Río at a ceremony in her home town of Castril, near Granada, according to the Cadena Ser radio station. The small civil ceremony was reportedly carried out because they had failed to register an earlier wedding in Lisbon.