The European Union has been given the green light to open full negotiations on a future trade deal with the Australia and New Zealand.

Brexiteers have trumpeted a trade deal with the two Commonwealth countries as a potential benefit of Brexit — but the EU will now have a year's head start on Britain in negotiations.

Britain is scheduled to leave the EU in March next year.

The European Union has beaten Britain to the punch in opening trade talks with Australia and New Zealand, after the European Council gave the green light to full negotiations between the partners on Tuesday.

Brexiteers had previously trumpeted a possible trade deal with the two anglosphere Commonwealth countries as a potential benefit of Brexit, but the EU will now have a year’s head start over the UK in getting a deal finalised – with an official ceremony due later this month.

The EU’s trade commissioner said she looked forward to welcoming the Commonwealth countries into the EU’s "ever-growing circle of close trading partners" after the Council approved the negotiating mandate, while critics back in the UK said the British Government had been "outfoxed".

Theresa May has claimed that Brexit "was the moment we chose to build a truly Global Britain" and hoped to secure trade deals around the world with other countries to make up for the economic hit from leaving the EU. Progress has been slow so far, however, with some partners like Japan saying they would prioritise the EU ahead of Britain, or others like the United States attaching difficult conditions.

Speaking as ministers from the EU member states signed off the start of talks, EU trade commissioner Cecilia Malmström said: "This is great news. We look forward to adding Australia and New Zealand to the EU's ever-growing circle of close trading partners.

"We are already close in terms of shared values and our open, global outlook. Together, we will now negotiate win-win trade deals that create new opportunities for our businesses, as well as safeguard high standards in key areas such as sustainable development.

"I am looking forward to visiting Canberra and Wellington in the coming weeks to officially launch our negotiations. Starting these talks between like-minded partners sends a strong signal at a time where many are taking the easy road of protectionism."

We look forward to adding Australia and New Zealand to the EU's ever-growing circle of close trading partners

In September of last year, European Commission president Jean-Claude Juncker proposed the start of full trade talks with the two countries. Preliminary discussions between Australia and the EU were already completed in April 2017, following an announcement of intention to start a trade deal by both actors in November 2015.

The Australian government says the EU is its largest export services market and also the southern hemisphere country’s largest source of foreign investment. Australian PM Malcolm Turnbull has meanwhile promised not to "muck around" in doing a deal with the UK, but talks are yet to begin because Britain cannot legally start them until it has left the union.

"Fantasy economic benefits of Brexit disappearing by the day"

Labour MP Gareth Thomas, former Trade Minister and a supporter of the People’s Vote campaign, said: "Once again, our International Trade Secretary has been outfoxed in his attempts to secure new post-Brexit free trade deals.

"The supposed economic benefits of Brexit rely entirely on striking new international trade deals, but clearly most countries are more interested in negotiating with the EU, the largest trading bloc in the world, than with the UK alone.

"With the fantasy economic benefits of Brexit disappearing by the day, but with the costs mounting up, this is yet more evidence of why we need a People’s Vote on the final Brexit deal."

The positive step for the EU comes weeks after the bloc jointly announced with Mexico that they were in the final stage of completing a trade deal.