Why 500,000 disabled people won't get to vote in May

In 2007, when Adolfo Barroso tried to vote for the first time, he was told his name did not appear on the voting list.

To have it added, the Spanish citizen was told, he would need to take a test: What is the speed of light? Who was Catherine the Great?

Between 23 and 26 May, hundreds of millions of Europeans will head to the polls to elect the next members of the European Parliament.

Some will also be voting in national elect...