UK Edition
The 5 Belgian regions which could block a Brexit trade deal
Under Belgian's federal system, there are five regional and language-based parliaments, all of which have the right to vote in matters of foreign affairs.
Belgium has progressively decentralised its political structure in a bid to end crippling squabbles between Dutch-speaking Flemings and French-speaking Walloons.
However, the country's complex system caught the world's attention in October as it struggled to sign off on a landmark EU-Canada free trade deal, after a number of regional administrations refused to give federal government the go-ahead.
The Comprehensive Economic and Trade Agreement (CETA), which had been provisionally signed off by all 28 EU countries was plunged into uncertainty following the decision of Wallonia, with a population of 3.5 million, to torpedo the deal.
It was finally signed at the end of October after Wallonia was given last-minute concessions to drop its opposition to the agreement.
The crisis led to fears that it could take a decade to secure a post-Brexit free trade deal with the European Union if a little-known region used its powers to intervene.
We've taken a look at the five Belgian regions who could block a Brexit deal.
Wallonia
Wallonia sustained its opposition to the trade deal until the very last minute of the crisis talks.
The region accounts for more than half of Belgium's territory and about 3.5 million of its 10 million population.
Once the country's economic dynamo, the region was badly hit by the closure of steel plants and coal mines at the end of the last century, and again after the 2008 financial crisis.
French Community
During the initial part of October's Canada-EU trade deal talks, the French-speaking community opposed the agreement.
Concerns were raised that the deal could give too much power to multinational companies and put pressure on governments.
At the time Ottawa’s trade minister walked out talks, declaring the EU “incapable” of managing international agreements.
Brussels
Belgium's capital city also opposed the deal during the final month of the negotiations.
Speaking during the deadlock, Belgium's Prime Minister Claude Michel said: "The federal government, the German community and Flanders said 'yes.' Wallonia, the Brussels city government and the French community said 'no'".
Canadian trade minister Chrystia Freeland walked out of the talks, which had been going on for seven years.
Flanders
Geert Bourgeois, the Prime Minister of Flanders, has proposed a radical North Sea Union linking Britain to a cluster of regional states to cushion the Brexit shock. The region is unlikely to seek to block a trade deal.
It was seen in the UK as an olive branch and a sign that European leaders are starting to look for creative ways to heal the referendum rift.
The leader of Belgium’s dominant region has said there is a growing consensus in EU capitals that it would be fatal mistake to try to “punish” Britain.
The federal government
The federal government holds the executive power in the Kingdom of Belgium in a similar system to the British one.
It is headed by an elected Prime Minister who appoints ministers secretaries of state.
Belgium famously went 589 days without a government in 2010-11.