Four decades after the end of the Franco dictatorship, Spain’s new government plans to open up more than 1,200 mass graves as part of a state effort to finally examine the dark chapter in the country’s history.

The Spanish justice minister, Dolores Delgado, outlined the basis for a 'truth commission' to address the legacy of the civil war and subsequent military regime, the exploration of which has for years been smothered by an amnesty law.

Issues surrounding the dictatorship, which ended following the death of General Francisco Franco in 1975, remain deeply controversial in a country said to have the greatest number of disappeared in mass graves after Cambodia.

Exhumations of the graves - believed to hold the remains of up to 140,000 people - have been strongly resisted by previous governments, while pro-Franco organisations continue to exist and dictatorship-era monuments loom large.

“It is not acceptable that people who are over 90 years old are in despair given that they will never recover their parents’ remains, or are faced with a ‘no’ from a judge or an arbitrary decision made by a local government,” Ms Delgado told a congressional commission late on Wednesday. “It is unacceptable for Spain to continue to be the second country after Cambodia with the largest number of missing people.”