City of London divided over Brexit

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It will be one of the most significant votes that parliament has held for many years.

Theresa May is on a mission. Now that her Brexit deal has been signed off in Brussels, she is determined to get it through parliament. But to have any hope of convincing the sceptics on both sides of the debate she knows she must first win over the people of Britain and their employers.

On it will depend whether we move forward together into a brighter future or open the door to yet more division and uncertainty.

No employers are more important than those in the City of London. It accounts for up to 20 per cent of the economy and in the last financial year generated £72bn of tax. An outcome on Brexit that is bad for the City will be bad for Britain.

The City of London is Europe's gateway to global capital. It's going to remain a great global financial centre whatever happens through Brexit. I'm not saying that we won't lose some business as a result of Brexit. Of course we will. We'll lose some business and some jobs as a result.

Many City financiers still bemoan the impending end of the UK's membership of the single market and its system of being able to sell products and services from London to clients across the EU under so-called passporting rules.

Well, we still think that the mutual recognition approach would have been the best, but that's water under the bridge because that's plainly not going to happen.

For Catherine McGuinness, policy chief at the City of London Corporation, it still clearly rankles that the government has been arguing in Brussels for a thin financial services deal based on maintaining parallel regulations, a so-called equivalence model, rather than mutual recognition, a more bespoke and ambitious concept that many financiers had lobbied for.

There's a lot wrong with the current equivalence model. It's intensely political. It's not permanent, and decisions can be withdrawn on as little as 30 days' notice. And it only covers about a third of the sector. But we've got to start from somewhere. There's an indication in what we've seen of the future framework of an intention to build on supervisory co-operation, regulatory co-operation. We've got to build.

For optimists, the most important part of the deal is the 21-month transition period that will follow Brexit in March 2019 because that will allow the skeletal principles of a future relationship in financial services to be built out into an enhanced equivalence arrangement, as they put it.

As it stands, the UK is leaving the single market. So the challenge now is how we move on to creating this new equivalence regime. I absolutely accept there are about half of this... about half a page of this in the political declaration, but that covers the whole economic relationship. And the critical point is, it's in there, and so we can build on it.

There is a hook for the negotiations. It talks about autonomy. It talks about a close, structured, regulatory relationship between the UK and the EU. And there are, of course, going to be negotiations around that. But the point is that we're moving, I think, in the same direction, and that is about making sure that there's the best possible - within the permutations and the limitations that we have - the best possible economic relationship on financial and related professional services.

Thin as the financial services model might look for now, most in the City feel that it's time to rally behind the deal that Mrs May has struck.

I think that finance has shown that it can adjust and build in significant change into its plans and future strategy.

The snag, though, is that parliament is rather less enthusiastic than the City. And that prospect has convinced many former Remain campaigners, and even some hardline Brexiters, that the right thing to do is to ask the country to vote again.

If parliament is unable to support the current deal, then I do think there is a case for a second vote, but only if parliament is unable to support the current deal because I think in those circumstances we're faced with a very stark choice, which is moving towards an exit of the EU without a deal. And I think that is a calamity, and I think that is a disaster. And that is something for which we are not ready and for which plans have not been properly made.

If we follow the path to a no-deal, financiers aren't really talking of Armageddon. They do stress there are some key outstanding issues relating to data access and the continuity of certain derivatives and insurance contracts. But banks, asset managers, and insurance companies have detailed contingency plans in place to cope with a cliff edge. One thing is for sure, though: the economic disruption of a no-deal Brexit will be significant. More jobs and activities will move to Frankfurt, Paris, and Dublin, and the tax take from the City in 2019 will not be £72bn.