Mr Johnson called the first December election since 1923 to break what he said was the paralysis of Britain's political system after more than three years of crisis over how, when or even if the country should leave the European Union.
The first exit poll, which surveyed 23,790 voters as they left 144 polling stations on Thursday, pointed to a 50-seat gain for the Conservatives to 368 seats.
Labour suffered its worst election result since 1935 and saw its vote share fall by eight points, while the Conservatives won a Commons majority of 80 - the party's biggest election win for 30 years - sweeping aside Labour in its traditional heartlands.
After Jan. 31 Britain will enter a transition interval throughout which it is going to negotiate a brand new relationship with the EU27.
Peter Kinsella, global Head of FX strategy at UBP said the pound's gains was a "relief rally" that the Labour Party under Jeremy Corbyn was unlikely to win and reflected the size of the majority the Conservatives looked set to claim.
If Johnson's guess on a snap election has paid off, he'll transfer swiftly to ratify the Brexit deal he struck with the European Union in order that the United Kingdom can depart on January 31 - 10 months later than initially deliberate.
While Brexit framed the election, the slow-motion exit from the European Union has variously tired, enthused and enraged voters while eroding loyalties to the two major parties.
Johnson toured a leftist bastion once represented by former Labour leader Tony Blair in a bid to show his intent to unite the country after years of divisions over Brexit.
Johnson's technique was to breach Labour's so known as "Red Wall" of seats throughout the Brexit-supporting areas of the Midlands and northern England the place he forged his political opponents because the out-of-touch enemies of Brexit.
A defeated Labour now faces a civil war between the socialists who control it and more moderate factions which will demand power.
Nandy, who has held shadow Cabinet positions in the past, took a more backseat role in recent times amid growing criticism of the Corbyn-led faction of the Labour Party.
"This is obviously a very disappointing night for the Labour Party with the result that we've got", Corbyn said after being re-elected in his own north London electoral seat.
Weary Labour candidates said his leadership had played a major role in the defeat.
The Liberal Democrats were forecast to win 13 seats, the exit poll said.
The party's ruling national executive is likely to take the final decision at a special meeting in early January.
The Brexit Party were not predicted to win any.
"Boris Johnson has to respect that the Scottish government in Edinburgh already has a mandate for a referendum on Scottish independence in a change of circumstances", said SNP Westminster leader Ian Blackford.
"Just as Boris Johnson was desperately seeking his majority, this result would give the markets their ultimate wish: clarity", said Dean Turner, Economist at UBS Wealth Management.