On Brexit day, the only departure in sight is the prime minister's

At 11pm GMT tonight Britain was supposed to morph into a proud sovereign nation once more, according to prime minister Theresa May's repeated promises. Yet the House of Commons has failed to find any meaningful consensus. It failed to deliver a no-deal Brexit, it failed to deliver a soft Brexit and it failed to deliver a second referendum. Businesses across the UK have been left exasperated and increasingly angry at the continued impasse and lack of clear direction. The big question, still, is what happens next.

On the day that Britain was supposed to have left the EU,  this  vote could be the final roll of the dice for May after two years of Brexit negotiations. The British prime minister has offered to step down as Tory leader, which may earn her some extra few votes from Eurosceptics within her party, but she needs a clean sweep from the Tories to get her deal through parliament.

A vote with no political declaration that is doomed to face the same results it yielded twice before on her withdrawal agreement: defeat.

Labour has already declared that it will vote against the treaty, calling the decision to split the vote "constitutional trickery". The DUP will also not back the deal.

MPs will be warned that failure to back the withdrawal agreement this time will lead to a long extension that requires participation in European parliament elections or crashing out without a deal on 12 April.

MPs who support a soft Brexit are meanwhile working on a new round of votes on the alternatives on Monday, including a compromise that could combine the support of those MPs who voted for a customs union, for Labour's Brexit plan and for the Norway-style option dubbed "common market 2.0".

The European Union's chief negotiator Michel Barnier has reminded UK MPs of the importance of today's Commons vote, implying that this is the last chance for Britain to secure an extension to the country's withdrawal from the EU.

Sterling will rally and the economy will have a growth spurt should Theresa May's Brexit deal pass today - but this could be reversed if Boris Johnson becomes PM.

This is the warning from Nigel Green, founder and CEO of deVere Group, one of the world's largest independent financial advisory organisations, on the day the UK was originally meant to have officially left the EU.

Boris Johnson has reiterated that he will back Theresa May's withdrawal agreement in Friday's Commons vote, following the arch-Brexiter's surprising about turn on this issue earlier this week.

He writes on Twitter: "It is very painful to vote for this deal. But I hope we can now work together to remedy its defects, avoid the backstop trap and strive to deliver the Brexit people voted for."

Nigel Green notes: "MPs will vote today on whether to accept the Prime Minister's version of Brexit, face crashing out without a deal on 12 April, a much longer extension, or a general election. No-one - really no-one - wants this uncertainty to continue.

"Since she vowed to quit, if has she gathered some more support in parliament, there is seemingly a gradual shift towards Mrs May's plan as it will allow the UK to leave in, supposedly, a more orderly manner."

He continues: "Should the PM's deal pass on Friday, sterling will rally and the economy will have a growth spurt as pent-up household spending and investment kicks in. 

"Domestic-focused small and mid-cap stocks would outperform large caps in a stock market rally."

He goes on to say: "However, the economic future of the UK now really depends on Theresa May's successor. 

"Boris Johnson, who is now also widely expected to be backed by arch Brexiteer Jacob Rees-Mogg amongst others in the leadership contest, is seen as the likely winner.  He would push for a much harder Brexit.  This can be expected to create more uncertainty, spook markets, and negatively impact sterling and UK financial assets."

Whatever next?
The deVere CEO concluded: "Whatever happens in the UK parliament with today's vote, or on Monday's, many question marks remain. We don't know who the successor, the one who will shape the UK's future relationship with the EU and global trading partners, will be, and what their approach will look like.

"This is why to mitigate risks and to take advantage of the potential opportunities the volatility is creating, investors must ensure their portfolios are properly diversified."

Janus Henderson's Brexit quick view is also very concise: "No, no, no, no, no, no, no and no"

"Sixteen different potential approaches to Brexit were presented to British MPs this week, eight were voted on yesterday - none received majority support. The Brexit process remains gridlocked," Paul O'Connor, head of Janus Henderson's UK-based multi-asset team, said.

"Advocates of softer forms of Brexit might take encouragement from the fact that the two most popular solutions were the one involving the UK remaining in a permanent customs union with the EU and another proposing a second referendum on the withdrawal deal.

"Still, these options did have more votes against them than in favour and it remains the case that a wide range of different outcomes are still plausible, ranging from the hardest "no deal" Brexit, to Theresa May's proposed plan, softer versions of Brexit or even to Brexit being revoked," he added.

As Britain's MPs try to break the deadlock over Brexit today, the outcome remains far from clear. The world of financial services will be hoping for some long-awaited clarity.