According to a Commons library research paper: "Dissolution may occur at any time; Parliament does not need to be sitting, nor to be recalled, for the purpose of dissolution.
"It is normally carried out by Royal Proclamation with the Great Seal affixed, and announces not only the dissolution but that orders have been given for writs to be issued for the summons of the new Parliament.
"The writs are dispatched by post from the Clerk of the Crown in Chancery and are delivered on the following day to the returning Officer for each constituency."
The dissolution will be marked in the City today by a reading of the Royal Proclamation by Colonel Tommy Tucker, the Common Cryer and Serjeant- at-Arms for the City of London, in a ceremony which dates back to 1309.
On Friday, there will be local publication of the notice of election, which is also the first day on which candidates can submit their nomination papers.
Candidates are required to be proposed and seconded by local voters, with eight locally-registered voters assenting. There are 44,203,694 registered voters in the United Kingdom.
The candidates' election deposit is pounds 500, and to save the deposit a candidate is required to win no less than one twentieth of the total votes cast in a constituency. In 1992, 903 candidates lost their deposits.
For registered voters who are going to be away and unable to vote on 1 May, the key date is Wednesday, 16 April; the last day for receipt of absent voting applications, which can be obtained from local town halls.
The deadline for receipt of those applications used to be Noon, but has now been extended to 5pm. For candidates, nominations close on the same Wednesday - but the deadline is 4pm.
Voters who are unable to vote on 1 May for unforeseen, emergency, health reasons, are able to get absent votes up to 5pm on 23 April.
A combined election will be held on 1 May, for the first time since 1979, with national and local elections coinciding throughout England.
All English county councils are facing election again, along with the reorganised, shadow unitary councils for Blackburn, Blackpool, Bracknell Forest, Halton, Herefordshire, Medway Towns, Newbury, Nottingham, Peterborough, Plymouth, Reading, Southend-on-Sea, The Wrekin, Thurrock, Torbay, Warrington, Windsor and Maidenhead, and Wokingham.