What is the CETA trade deal and why could it be significant for the UK's Brexit talks?

Trade talks aimed at establishing a free trade zone between the EU and Canada have broken down today, casting a pall over the British efforts to strike a new deal with the bloc after Brexit.

Here's all the essential details on what exactly the planned trade deal involves - and why it's success or failure could be so significant for the UK's own negotiations.

• What is the proposed CETA deal?

The proposed Comprehensive Economic and Trade Agreement (CETA) would set up a free trade zone between the EU and Canada.

It would mark the first time the bloc signed such an agreement with a major economy outside the EU.

• Why is it significant for Britain's Brexit talks?

The talks are seen as a litmus test of Brussels' ability to reach agreement on any major deal with an outside country.

Given that the vast majority of the EU is strongly in favour of approving open trade with Canada, a failure would bode badly for Britain as it tries to forge its own deal to keep open trade links after it leaves the bloc.

• So how are the talks going?

Very badly, it would seem.

Canada's trade minister Chrystia Freeland said that the planned deal had failed as she walked out of meetings with southern Belgian politicians today who are currently blocking the deal.

She told reporters the EU was "not now capable" of striking an international trade accord even with a like-minded country.

“Canada is disappointed and I personally am disappointed, but I think it’s impossible,” she told reporters as she left.

“We are returning home.”

The European Commission has tried to play down the row, saying that the discussions were currently halted but had not been abandoned.

• What are the problems holding up the agreement?

Despite all the countries within the EU backing the deal, talks have ground to a halt largely because a single region of Belgium strongly opposes it.

The regional government of the French-speaking region of Wallonia has steadfastly refused to give the go-ahead over fears that it will harm local workers and give power to multinational organisations at the expense of individual states.

Belgium's political structure means that it cannot approve the deal without all the five regions' approval, even though the central government wants to go ahead.

• Is that the only thing holding back agreement?

No. Romania has also been pushing for agreement to include free movement of people between EU states and Canada.

There have also been protests from activists who claim that the agreement would open a "race to the bottom" over workers' rights and environmental standards.

• So where does that leave the deal - and Britain?

The EU says that it will continue to make efforts to reach agreement, but hope is gradually fading that it can reach consensus.

It means that Theresa May has a big job on her hands as she attempts to persuade EU leaders to sign up to a deal that would allow the UK open trade links with the bloc while also restricting migration.