Britain is leaving Europe, but it’s hardly leaving Brussels.

The U.K.’s diplomatic footprint in the European capital — currently hidden behind a congested Brussels roundabout, stretched above a Lloyds pharmacy and a cheap Belgian brasserie — will be bigger than it ever was. Come March 29 of next year, the U.K. Representation to the European Union will be the crown jewel of Britain’s global diplomatic network, say senior Whitehall officials, ministers and diplomats.

The British push to beef up its Brussels presence reflects anxiety in London about being left out of the loop on EU matters of huge importance to the U.K. once its officials and politicians lose their automatic seats at the institution’s tables.

“There are endless meetings about what’s going to happen as a third country mission,” said one senior U.K. official familiar with the ongoing discussions about the future of what’s known as UKRep. “It’s quite high-level stuff but there’s no doubt it’s going to have to become very, very substantial. There’s no doubt it will have to get larger — a lot larger.”

Across Europe, London has created 50 new diplomatic posts, costing £4.1 million.

Some officials and MPs say UKRep will soon rival the biggest British embassies in the world, in Washington and Beijing. The EU is, after all, Britain's largest trading partner.

Even as British “Leavers” blast Brussels bureaucracy, London is expanding its bureaucratic footprint on the ground in the EU capital. In the two years since the referendum to pull out of the Union, UKRep has boosted headcount from 120 staff in 2016 to 150 today. Diplomats say it will continue to expand, but don’t put precise numbers on it. Across Europe, London has created 50 new diplomatic posts, costing £4.1 million, Simon McDonald, the most senior official in the Foreign Office, confirmed in a letter to the House of Commons foreign affairs committee Chairman Tom Tugendhat in March.

Whitehall turf battle

What exactly UKRep’s future expanded role should be, and whom it should report to, is a matter of debate in London. It’s part of a wider Whitehall turf war for control over Britain’s relationship with the EU. The Foreign Office, the Cabinet Office and even the Department for International Trade are vying for the spoils from the expected breakup of David Davis’ Brexit department once Britain leaves the bloc.

In its current incarnation, UKRep's chief, Tim Barrow, reports to Davis, although the institution itself is paid for under the Foreign Office budget. It operates as something of a halfway house between a domestic government agency and full-blown foreign embassy, stuffed with technocrats from across Whitehall to help draft EU rules and regulations.

After Brexit, this role is dead.

“We are going to have to completely rethink what we do,” one U.K. official said of UKRep’s future role. “We are going to need new skills, the best diplomats we’ve got, to find out what is going on now that we’re no longer sitting at the table. The whole purpose is going to change.”

The name is going to go, too, officials say. One well-placed diplomat said it would probably be renamed “the U.K. Mission to the European Union,” and given an enhanced role as London’s eyes and ears in Brussels.

At the heart of the debate is not the name though, but what exactly UKRep will be tasked with doing. With the outcome of talks over the Brexit withdrawal agreement still murky, that remains unclear.

In the ongoing confusion, British officials across Whitehall have been calling their Norwegian and Swiss counterparts — both countries are outside the EU but either inside the single European market or with very close ties to it — on a “daily basis,” trying to understand what life outside the bloc looking in entails, two diplomatic officials said on condition of anonymity.

Boffins or plenipotentiaries

The practical issues of how many staff and what kind the mission will be needed in future speak to the bigger question of Britain’s role in the world and how it wants to achieve it.

Tugendhat, the chair of the foreign affairs select committee, has publicly called for a more expansive foreign policy effort after Brexit.

“The success or failure of our foreign policy is now more important to the future health and prosperity of our nation than it has been at any time since the end of the Second World War. We need to make the Foreign Office the strategic engine of our foreign policy again,” he said in a speech in May.

Whether such a large strategic shift happens or not though, UKRep will need to change, say insiders.

“There’s an interesting question about what type of individual UKRep will need," according one diplomat. "At the moment it’s an across-Whitehall operation, but you’re going to need more than technical experts after we’ve left [the EU]. When we’re not part of the EU structure we are going to have to find out what is going on inside."

One Conservative MP and former minister said Brexit would reshape Whitehall from top to bottom. UKRep would be just one of the affected institutions.

“This is the great irony of Brexit, and something the government has not had the guts to level with people,” the MP said. “Far from there being a Brexit dividend for the NHS, we’re going to have to ramp up spending on things like foreign embassies.

"You didn’t see that on the side of a bus did you,” the legislator deadpanned, referring to the Leave campaign’s bus advertisement that promised billions in savings from Brexit.