James Landale, diplomatic correspondent, BBC News, says there are few places more fun to be posted than London right now

Bliss it was in that dawn to be in London. But to be a diplomat was very heaven! Brexit may have been a cause for gloom and despondency in many European capitals. But for the diplomatic corps, what larks! The rarely spoken truth – confessed only privately by a handful of honest envoys – is that Britain’s departure from the EU will probably mark the peak of their professional careers. And what’s not to like? Governments need their eyes and ears more open on the streets of London than perhaps ever before. Twitter may have transformed relations among nations as much as the telegram (pace Tom Fletcher) but Brexit will require as much diplomacy as negotiation. Brexit is, ahem, good for trade.

European leaders will want to know every bit of intelligence their official representatives can send their way, every nuance and analysis of the British government’s thinking, every piece of gossip that could give them an edge. In chancelleries across the continent, diplomatic dispatches from London will be read the moment they land on desks. As many diplomats would admit, this is not true of ‘diptels’ from every posting.

There is also – it must be said – an entire new branch of diplomacy opening up. Where once the UK acted with the EU, it must now be ready to don a bilateral hat and do things for itself. There will be a lot more UK activity for EU diplomats to monitor which beforehand would have been a routine part of regular European councils. If ‘Global Britain’ means anything, it means a lot more work for diplomats in London trying to keep up.

And that is just the new world for those envoys representing the remaining 27 member states. Something often forgotten about Brexit in the solipsistic European debate is that it affects other continents too. Diplomats from the Gulf are chafing with excitement at the prospect of deeper trade arrangements with the UK. Envoys from the Commonwealth are looking on with concern about continued access to EU markets and with enthusiasm about greater access – potentially – to UK markets. Officials representing Asian countries are trying to work out if the UK government’s optimism about Brexit is so much hokum and whether they need to start relocating their businesses elsewhere. Partners in the World Trade Organisation are scratching their chins and wondering how their tariff rate quotas might be divided up – or not. And everyone else is watching and waiting.

Brexit has thrown so many established political relationships into the air that it has fallen to this generation of London’s diplomatic classes to interpret – and let’s be honest – sometimes to guess where the cards may fall. To quote the Nobel Laureate, Mr Dylan, “the wheel’s still in spin, And there’s no tellin’ who that it’s naming.’”

So beneath the heavy hearts and slumped shoulders of Europe’s diplomatic cadres there are hands being rubbed with professional glee at the technical challenge ahead.

And what a challenge it will be. Brexit is being presided over by an administration in Downing Street that hoards information and almost makes a fetish of keeping cards close to its chest. On one occasion Theresa May was reported to have refused to tell even The Queen about her plans for Brexit.

If the Prime Minister would not even gossip with Her Majesty, what chance His Excellency?

The risk here is that London’s diplomats lose the battle of expectations. As their governments demand ever more information, the more tight-lipped Whitehall becomes. The danger is the diplomat will be asked by his or her master to become a soothsayer, relying too much on nuggets from journalists and think tankers and lobbyists and all the rest of us of who suck at the ever-growing teat of the Brexit sow.

Pity, too, the diplomat who has to plough through the steady diet of parliamentary reports on Brexit. The Institute for Government has counted no fewer than 55 separate select committee inquiries into all aspects of Britain’s departure from the EU. Some may be repetitive but they all must be read. And that is on top of all the research outfits, City analysts and academics who are churning out paper at a rate of knots.

But to the top-flight diplomat, this is all chicken feed. What they want is top quality gen from the horses’ mouth. So, the hope among those accredited to the Court of St James’s is that while ministers may try to maintain their Zen-like discretion, the civil service will show a little more ankle. The man in Whitehall may not know best anymore but he does at least still know what is going on.

The other risk for London’s diplomats is that Brexit might get rather bloody. The negotiations may seem arcane and detailed to some but they are mostly about crude power. Who decides? Who pays? Who comes first? And who comes last? This will not just test professional relations among governments but also personal relations between officials. Few diplomats enjoy being caught between the wishes of their masters whom they represent and their host governments whose guests they are. So, while Brexit may be fun, it could also get rather brutal.

But these are mere details. For the professional diplomat, I can think of few places it would be more fun to be than London. Washington, of course, is interesting and unpredictable. Moscow is forever intriguing. But London in 2017 has few rivals. Perhaps Vienna in 1815 might have been more exciting. There certainly would have been more sex – it was not called the Congress of Vienna for nothing – and a greater chance that if diplomacy failed then armies would march. Few would dare say that about Brexit. But the passion and politics and professional challenge that London poses to the modern-day diplomat can have few rivals.

So now we know: Brexit doesn’t just mean Brexit, it also means more diplomacy. And for their excellencies, that is excellent news.