Section 2 of the Act specifies when an early election may be held. An early parliamentary general election is to take place if -
(a) the House of Commons passes a motion in the form set out in subsection (2), and
(b) if the motion is passed on a division, the number of members who vote in favour of the motion is a number equal to or greater than two thirds of the number of seats in the House (including vacant seats).
(2) The form of motion for the purposes of subsection (1)(a) is—
“That there shall be an early parliamentary general election.”
Politically, a general election campaign enables EVERY aspect of political life to enter the fray and experience shows that events can take unexpected turns. Naturally enough the BIG question will be BREXIT which continues to divide the nation. A return of a Conservative government will be seen as endorsement of Brexit. If some other party forms the next government or if a further coalition government comes about then the future will be extremely interesting indeed.
If the vote in the House of Commons is in favour of an early election then Parliament will be dissolved in accordance with section 3. This is the only way by which Parliament may be dissolved. The former prerogative power of the Crown to dissolve Parliament has been replaced by the 2011 Act. The prerogative power was exercised by Her Majesty acting on the advice of the Prime Minister of the day.
Postscript 19th April:
The Fixed Term Parliaments Act was enacted after the coalition government (2010-15) was formed. Essentially, the Act prevented the Prime Minister from deciding to call an election at a time that might benefit his own political party (Conservatives) at the expense of the other political party in the coalition (Liberal Democrats). Although the coalition government ended in 2015, the Act remains in force and will do so unless and until it is repealed. See this Summary of the Act and the Background to the Act. For a fuller examination of the Act see Carl Gardner's book "What a Fix Up"
Earlier this year the Charon QC blog commented about the book - “What a Fix-Up!” is an-depth analysis of the Act, an alarming description of the risks it creates, and a passionate argument for its repeal."
Another good read is at UK Constitutional Law Association - Jeff King: May's Gambit - J. King, ‘May’s Gambit’ U.K. Const. L. Blog (19th Apr 2017) (available at https://ukconstitutionallaw.org/)).
and Paul Reid examines the relationship between elections at Westminster and Edinburgh - Paul Reid: How fixed is a Fixed-Term Parliament? P. Reid, ‘How Fixed Is a Fixed-term Parliament?’, U.K. Const. L. Blog (20th Apr 2017) (available at https://ukconstitutionallaw.org/))