A successful Brexit may still happen as the EU says Wallonia hasn't killed the trade deal just yet

A single regional government in Belgium looked like it killed off all hope that Britain will be able to strike a trade deal with the European Union after the Brexit is complete.

That's because Wallonia, in Belgium, rejected a the EU-Canada Comprehensive Economic and Trade Agreement, or CETA, last week and then for a second time on Monday. It means the deal, which has taken 7 years to negotiate, could collapse, as all areas of Europe must ratify it.

The 7 year's of potentially wasted work highlight just how hard it will be for Britain to do a deal with the EU after it leaves the 28-member bloc.

But European Council President Donald Tusk said on Tuesday that he and the Prime Minister of Canada, Justin Trudeau, are hoping that Wallonia will change its mind on Thursday:

CETA was all but done and just needed to be ratified by all EU member states before being implemented.

But Wallonia, which is one of Belgium's six legislatures, refused to support CETA on Friday after having vetoed it earlier in the week, meaning Belgium's national government cannot approve the deal. Charles Michel, the Belgian prime minister, confirmed on Monday afternoon he was not able to sign the agreement.

It's another reminder of how difficult the Brexit negotiations will be for UK Prime Minister Theresa May's government. Even if May can get a deal on favourable terms with the EU's negotiating team, there's no guarantee it will pass.

Belgium, like other EU member states, operates under a federalist political system. This means that significant powers are granted to regional governments, allowing them to block legislation at the national level.

Linda Lim, trade expert and professor of strategy at the University of Michigan's Ross School of Business, told Business Insider earlier this week: "If this [CETA] doesn't go through it makes it much more difficult for Britain to negotiate something with the EU."