Reviewed by Dave Hill, Society Trustee and editor of On London

What if London became in independent city state? The first speaker at the event addressing that question, presented by On London and The London Society, was Nick Bowes, chief executive of Centre for London and previously director of policy for Mayor of London Sadiq Khan. He imagined "a pretty progressive" new metropolitan country with liberal drug and immigration policies that would quickly join the European Union and perhaps even adopt the Euro as its currency.

It would be a wealthy country too: the £30-£40 billion in taxes raised in London every year that subsided almost the whole of the rest of the country prior to the pandemic - and will probably do so again - would no longer be exported but spent within London itself. "Imagine what you could do with that," said Nick. "Imagine how you could transform public services. It would be enough to pay for Crossrail 2 in one go, with enough left over for the Bakerloo Line extension too."

The list went on: the cash to utterly transform public services and affordable housing supply; the freedom to reform Council Tax; to introduce private sector rent controls, if that seemed a good idea; the ability to more tightly regulate mysterious offshore property ownership.

Catherine McGuinness, a City of London ward councillor and, until recently, chair of its key policy and resources committee, adapted Boris Johnson's reported drafting of two arguments about EU membership - one for remaining, one for leaving - to focus in her own mind the respective cases for London leaving or remaining in the UK.

"Breaking the shackles of an over-centralised Britain" seemed to her a tempting reason for leaving the UK, especially in light of the escalation of anti-London rhetoric in recent years and specific policy actions, such as reductions in Arts Council funding and the ending of VAT-free shopping for overseas visitors, which is hurting our retail sector. A London gone solo might, Catherine thought, be better able to "build on our position as a global powerhouse, comfortable with our diverse community, both those who’ve been here for a long time and those who’ve joined us".

Even the conundrum that would be created about the royal family could perhaps be neatly dealt with. The centuries old City struck a deal with William the Conqueror , whereby it recognised him as King William I and he recognised the City's existing rights. Might the UK's new monarch settle for being its King Charles III and also King Charles I of the new state of London?

Professor Tony Travers of LSE London enlarged on the governance and constitution theme, envisaging preparations that would have to be made in advance of an impending referendum outcome paving the way for a London breakaway. Would such a London want a monarchy at all? Would it want a presidential system of government or something more like parliament, with a legislature and Prime Minister?

London's boroughs would find their status changed, becoming subsidiary to the government of London rather than being separate government bodies in their own right, "The city state government would decide what powers the boroughs would have, how they raised their money and regulate them,” Tony said. A London government civil service would have to be created too.

As for the newly London-less UK, it would have to decide on a new location for its centre of government, packing its bags and leaving Whitehall. How about Watford? Or Crawley? Or Milton Keynes? And like Nick Bowes Tony emphasised how rich the state of London would be: "It would be possible to replace the English National Opera’s lost funding 3,000 times over.”

But all the panellists were frank about the downsides of leaving. Drawbacks described included the possibility of passport checkpoint tailbacks at the M25 affecting the million or so workers who commute in to London from elsewhere everyday and the visitors from other parts of Britain who help fuel the capital's economy. It would suddenly really matter that three of London's international airports aren't actually in London. At present almost all of London's energy and food is supplied from beyond its borders. Joining the EU would create an encircling hard border with a worse-off and perhaps resentful England, which might extract high prices for permitting the import of vital needs through its territory and airspace.

Jenna Goldberg of London Communication Agency articulated a broader objection, warning against buying into the "culture war, London versus everybody else" narrative that informed the EU referendum outcome and has fed into the "levelling up" debate. "I am a born and bred Londoner," she said. "But that’s not how I define my relationship with the UK."

She also foresaw difficulties arising from a dimension of the multi-diversity that make London distinctive and different in the first place. Many residents of Bromley, Bexley and perhaps Conservative-leaning voters in central London might be unhappy against the prospect of near-certain left-leaning London national governments and their values, sharpening divisions within the nascent city state.

The same could go for the government itself. "If there’s one thing we’ve learned about people with left progressive values, it is that they are very good at fighting among themselves," Jenna observed. "We would probably have quite a left leaning government that very quickly separated itself into several different factions”. She also feared a loss of London's cultural "soft" power if UK national institutions were moved elsewhere. She described those things as "part of our identity and our whole city. Perhaps it would run the risk of becoming a colder and less charming place to be.”

Pushed from the floor by My London City Hall editor Josiah Mortimer, all four panelists plumped for London staying in the UK - in contrast to the audience of around 70 people at at The Gallery at Alan Baxter Associates on Cowcross Street, which was split pretty much down the middle - but all picked up and ran with the subliminal thread of the discussion, which was about the desire for greater devolution of powers to City Hall - and Whitehall's extreme reluctance to provide it - and London's relationship with the rest of the country.

Serious points were raised by panellists and audience members alike about, for example, Hamburg's powers and responsibilities within Germany, the process and outcomes of Singapore's separation from Malaysia in 1965 to become a republic, and the status of Crown Dependencies. Responding to a question from London Society chair Leanne Tritton, Catherine and Nick said London needs to find better, more persuasive language and arguments for endearing itself to parts of the UK that feel negatively towards it. There was short speech from the floor by Tom Foster, leader of the election-fighting Londependence Party.

There was also time and space for a bit of fun. Jenna suggested Stephen Fry as a possible non-political head of state, or maybe Vivienne Westwood. And what about a national anthem: the nominees on the night were Parklife, Strange Town, Waterloo Sunset and London Calling. The Clash prevailed by a small margin over The Kinks.

That was, perhaps, appropriate. London is most definitely calling, if not for independence, then certainly for more autonomy. If national government continues hogging power for itself, who knows what secessionist urges might emerge?