Britain already has one of the lowest turnout record of any country in Europe, but it is highly unlikely that the government would go as far as some of its EU partners and make voting compulsory.

BBC: Low turnout boosts Labour plans to change system

Abstention in Chile's national elections has been rising, even though voting is compulsory.

ECONOMIST: Consternation

In theory, that question is irrelevant in Brazil, since voting is compulsory.

ECONOMIST: Brazil's presidential election

Australia is the only major democracy to use the same type of AV system as the one being proposed for the UK, but voting is compulsory there.

BBC: Q&A: Alternative vote referendum

Voting in the referendum was compulsory.

BBC: 1950: Government falls as Belgians vote for king