Update (5pmET): The first exit polls are in...and by the looks of it, the Conservatives will walk away with a sizable majority, with 368 of the Commons 650 seats.

With a predicted majority of 86 seats, this would be the biggest majority for the Tories since the days of Margaret Thatcher.

Political analysts on Sky News are already lauding Johnson's stunning political comeback

Unsurprisingly (and in accordance with our trading guides posted below), cable has exploded higher as it looks like Boris Johnson has led Tories to a "stellar" performance. The pound jumped 2.2% to the $1.3450 level. It's an insane move in cable - its largest one-day jump since January 2017, and that's especially alarming when one takes into account the fact that economic data still show the UK sliding into recession.

But let's not forget: If these results are confirmed, then Johnson may have delivered something investors have been wanting since referendum day - a stable working government.

Plus, now there's little doubt that Johnson will manage to push his Brexit deal through the Commons.

The British currency is trading at its highest level against the dollar since June 2018. Against the euro, the pound has reached its strongest level since the aftermath of the 2016 EU referendum.

If the pound holds on to these gains, we could see the biggest one-day jump since March 2009.

If the pound holds onto these levels - it would be the biggest one-day gain in $GBPUSD since March 2009. Surpasses previous biggest gain since Brexit referendum (17 Jan 2017 - Theresa May's Lancaster House speech). Pound hasn't been this strong against $EUR since July 2016 pic.twitter.com/2TEEhSP3Eo — Viraj Patel (@VPatelFX) December 12, 2019

Looking ahead, analysts are saying that GBPUSD could climb past $1.36 throughout the night if the results confirm the exit polls. On the other hand, any polls questioning the size of the Tories' majority could trigger a pullback. We imagine that, on a night like tonight, traders (both and human and computer) will exhibit a hair trigger. Newcastle and Sunderland, two cities roughly 15 minutes apart, are expected to report the first official results around 11.

But with no official results reported, complacency is already sinking in.

"The numbers that people expected were 330, maybe 350, so to see 368 on the screen is incredible," wroteNomura's Jordan Rochester, aka "Mr. Brexit". In a note to his clients, Rochester advised them to "go home folks, pop open a bottle of wine, and get a night's sleep." We imagine Rochester will remain vigilant and at his desk, as he told the BBC.

The exit poll also points to sizable gains for with the SNP, which is slated to win 59 seats, up from 55 presently. According to the FT, the combination of a Tory government and a nationalist surge in Scotland will likely revive pressure for another independence referendum.

While the SNP and the Conservatives both have reason to celebrate, the results for Labour are nothing short of appalling . You'd need to go back to 1935 to see another Labour result that bad. Falling below 200 seats would be a major blemish on Corbyn's legacy, and it's very possible that, after tonight, Corbyn's days as leader will be numbered, with some analysts saying that he has to resign after this.

The Lib Dems don't have much to brag about either, appearing to have gained just one seat, moving from 12 to 13 MPs.

As Johnson and his team bask in the adulation from the media and political analysts fawning over his still-uncertain accomplishment (though a margin of 86 is well outside of the exit poll's margin of error for a Conservative majority), somewhere in the UK, Theresa May is probably lighting a blunt in front of the TV and starting to giggle...

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Update (4:50pmET): With the first exit polls expected in around 10 minutes (Not long after the last UK polls close), traders can follow along with live coverage below:

For those planning to trade through the night, here's a traders' live feed from Amplify Trading:

Meanwhile, here's an abbreviated timeline for what traders should be watching out for in the coming hours (courtesy of Akera FX and Global Macro Strategist Viraj Patel).

🔵 $GBP & #GE2019 Thread🔴

⏲️ 10pm: Exit polls. Watch Tory majority size. 2017 exit poll had Tories at 314 vs 318 actual

⏲️ 11pm: First results. Labour strongholds (focus on vote margin)

⏲️ 3-4am: Tories should build lead if on track for +40 seat majority

*Updates next 24hrs* 1/ pic.twitter.com/HBCzLfDqpN — Viraj Patel (@VPatelFX) December 12, 2019

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Update (2:25pmET): With the first exit polls expected in fewer than three hours, the pound has extended its drop as traders abandon their positions ahead of what's expected to be a wild night for the British currency.

The pound was recently down 0.8% against the greenback at $1.3093. It was also down 0.6% against the euro, buying €1.1785, though over the past half hour, it appears to have bounced off its lows as traders adjust their positioning before 'go-time'.

The first polls are expected at 10 pm London Time, and are expected to provide a first look at the results of what could be a closely fought election. The last batch of polls famously suggested that a hung Parliament - one where no party wins a majority - remains within the margin of error. Still, the currency has rallied sharply since September and is up 10% from a low below $1.20 reached in early September.

As traders try to make sense of the early exit polls, the FT reminds us that, for markets, the most important area to focus on is Labour's "red wall" in the north and center of England.

In the last election, the Tories flipped seats in Middlesbrough South and East Cleveland, which turned blue for the first time in 25 years. The seats to watch are between the Vale of Clywd in northern Wales, through Merseyside to Great Grimsby in Humberside. The ridge touches 50 constituencies the Tories hope to win. In the West Midlands, Mr Johnson needs just 22 votes to win Dudley North. The Labour majority in Crewe and Nantwich in the north-west is only 48 votes; Stockton South in the north-east requires 888 votes to change hands - seats which voted to leave the EU in the 2016 referendum.

This map has more on that:

The Times of London has built an interactive map showing how seats have changed over time. As they remind us, there are 63 seats that have consistently backed the prime minister in every election dating back to 2005, when Tony Blair won his third term in a landslide victory.

Traders around the world are expecting to put in 24-hour shifts just to trade the pound through what could be a dramatic night. For everybody who hasn't been following every pip in cable since the summer, Bloomberg has a guide to the key levels traders should watch out for as the results come in (courtesy of Vassilis Karamanis, an in-house FX and rates strategist at BBG):

Bullish:

The first key technical resistance for the pound comes around $1.3380-90, where the year-to-date high and an Elliott Wave 5 projection coincide.

First, pivot resistance at $1.3278 may absorb some buying pressure; a crucial level to watch out for is $1.3453, which represents the key 61.8% Fibonacci retracement of sterling’s losses since April 2018

Also in play could be the 55-monthly moving average, now at $1.3412

Bearish:

Investors short the pound may be looking to trim their exposure only after the upper end of the symmetrical triangle that kept the currency confined before Dec. 3 is breached; this is currently seen at $1.2964

Strong support should be met around or within $1.2756-$1.2806, an area that includes the 55-daily and 55-weekly moving averages as well as the low on Nov. 8

Support from a three-month trend channel comes at $1.2627 while the Sept. 20 high -- also a breakout point -- is seen at $1.2582

Range-bound:

In case the pound fails to sustain a big move in either direction, short-term levels to watch for include $1.3013, the Oct. 21 high; $1.2993, the 21-daily moving average; $1.3232-37, Upper Bollinger Band and pivot resistance

Source: Bloomberg

We'll have more once the first exit polls trickle in.

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For FX traders, the big day has finally arrived. With FX volatility nearing all-time lows, Britons will head to the polls on Thursday in the first general election since 2017.

As the chart below shows, the results of this election could have profound implications for the British currency.

In a sign that few traders are betting on a sure thing, cable risk reversals show hedging activity has hit its highest level since the EU referendum in June 2016.

For ordinary Britons, the big day marks the culmination of a five-week campaign that has left many exhausted from overexposure.

One truck driver who spoke with the AP wearily expressed his frustration at the British political establishment.

"Basically I just want it over and done with now," he said. "Nobody’s doing what they said. Everybody’s lying."

Compared to its US equivalent, the House of Representatives, there are a lot of delegates in the House of Commons. British elections are decided by the outcomes of races in 650 districts. Most won't change hands. Only 70 did in 2017, and 111 in 2015. But, as Bloomberg explains, "it's the ones that do that determine who governs."

Unfortunately for traders in Europe, that won't begin to take shape until early tomorrow morning. According to Bloomberg, most of the early reporting districts have safe majorities. But an exit poll will be released as soon as voting ends, giving traders an idea of whether the Tories secured a clear majority, or whether the final total will be close.

According to the FT, Johnson pleaded with voters on Wednesday night to deliver a decisive majority for the Tories, which would allow the PM to take Britain out of the EU in January and start the task of negotiating a new trading relationship with the 27-member bloc.

Johnson has based his campaign on a promise to improve Britain's position in the world. He has promised to establish a looser relationship with Europe and closer ties with President Trump's US. Meanwhile Jeremy Corbyn, the leader of the opposition Labour Party, is pushing an agenda that has been described as socialistic.

"If we can get a working majority, we have a deal, it’s ready to go," Johnson said Wednesday as he watched pies being baked at a catering firm in central England. "We put it in, slam it in the oven, take it out and there it is - get Brexit done."

Polls have shown the Tories with a clear lead, though that has apparently narrowed in recent weeks, with a poll released late last night revealing that a hung parliament - ie a situation where no party wins an outright majority - is still a possibility.

There has been an unprecedented get-out-the-vote effort in the UK during the five-week campaign, which is one reason analysts have warned that the polls should be taken with a grain of salt.

A YouGov survey using modelling that was successful in predicting the result of the 2017 election showed on Tuesday that the Tories were on course to win 339 seats, Labour 231, the Liberal Democrats 15 and the Scottish National party 41, during the upcoming election. That would suggest a Tory majority of 28, down sharply from the 68-man majority predicted in an earlier poll.

Corbyn is offering old-school socialism, including a big expansion of the state, the nationalization of industries including water, energy, rail, broadband and postal services, and hundreds of billions of pounds of extra borrowing. Labour has relied on a message claiming this is the "most important election in a generation" to try and turn out as many young idealists as possible (take a look at the Guardian for more Labour messaging on display).

During the campaign, the Tories have targeted a type of voter known as the think-tank approved "Workington Man." Voters who meet this characterization are defined as "typically older, white, non-graduate male" from a northern town. The man is named after Workington, a town on the UK's west coast.

The town has taken on outsize importance because it's one of the first constituencies to report in the UK's "Wall of Red" in central and northern England. Traditionally Labour-supporting, Johnson must break through and lead the Tories in these districts to victory if he hopes to secure a wide ruling majority.

As Thursday morning wore on, the pound extended its losses to trade down 0.6% at $1.3116 before paring declines. Analysts blamed the drop on a rebound in the dollar, bolstered by comments made during Christine Lagarde's first press conference as ECB president.

On the other end, EUR/GBP climbed 0.7% to £0.8491, looked set to climb third day.

For a rundown of the most important districts and when to expect results, see the chart below: