The U.K.'s "first-past-the-post" voting system was designed for two-party politics, so when several parties contest a British election, results do not necessarily reflect the popular vote.

According to final results released on Friday, the Conservative Party gained 331 seats, enough to form a single party government. Labour came in second 232 seats.

But the popular vote was split between the two major parties, with the Tories at 37 percent and Labour at 31 percent according to latest count of votes broadcast by BBC.

Results coming through Friday showed an outcome unpredicted in opinion polls before the election, with the Conservatives showing an unexpected level of success and Labour and the Liberal Democrats left devastated in what many observers said was the biggest surprise in a general election since 1945.

Why doesn't the division of seats in parliament reflect the popular vote?

The Electoral Reform Commission has been trying to change the system for years, running a referendum on electoral reform in 2011. But British voters rejected electoral reform in the poll.

The current system is the result of election laws that were enacted in 1832, 1867 and 1884.

The British system divides the country into legislative districts with each being represented in parliament by a single MP.

If a number of parties contest a seat in a district, the winner is the candidate who receives the most votes within the district.

The system differs from those in Continental Europe, where voters rank candidates on a ballot form in many states.