You can argue it either way. On one hand, the forward march of the UK economy, and the inability to develop a coherent negotiating position, militate in favor of a relatively quick and condition-less Brexit. The European Union is not offering any very flexible intermediate deals, perhaps to punish future would-be leavers. On the other hand, the consequences would be sobering (FT):
Research by the FT shows the scale of the UK-based banks using passporting to sell into the EU. The group of 96 banks has assets of £7.5tn, directly employ more than 590,000 people and make annual profits of around £50bn.
Bank executives say EU passporting makes up 20-25 per cent of the London business of international investment banks, including the five big US players, who have assets of £1.5tn and staff of 21,000 in their UK-based banks, and the two big Swiss, which have assets of £415bn and staff of more than 6,000.
…John Holland-Kaye, chief executive of Heathrow, warned that leaving the EU customs union would “add massive overhead” for businesses and port operators. “Can you imagine operating something like the Euro[tunnel] if you had to suddenly build in all these checks in place? It would be completely unmanageable,” he told the FT.
This explainer of the “gravity model of trade” shows the UK could not make up lost EU business elsewhere in the world. Oil and a few other commodities aside, you trade with the countries that are next to you.
Overall, the Brexit stakes are higher than a few months ago, and that is making the final outcome harder not easier to predict.