The Prime Minister addresses with the formal request to the sovereign (monarch) to dissolve parliament (распустить парламент). When parliament is dissolved, all its members become unemployed, but the government continues to work. Then manifestos of parties are published, and then, around the whole country begins pre-election campaign which proceeds for about 3 weeks. It is widely covered in the press, radio and TV.
( Освящаться прессой, на радио , ТВ )
Voting is carried out in the Election Day, usually at Thursday. Voting results (ballots )in each electoral/election district are informed as soon as voices are counted up as a rule at the same evening.
Results of elections in the country are informed the latest next morning.

как точнее перевести последнее предложение: Результаты выборов по стране сообщаются самое позднее на следующее утро.

The PM formally requests the sovereign to dissolve the p...

upon/after dissolution ....

then the election manifestoes are ....

election campaign...

covered by media...

in each electoral/election district -- for each constituency...

The results are announced no later then the following morning

Since 1945 the ruling party and Opposition were only 2 parties: Conservative and Labour. In 1980s Margaret Thatcher served UK politics. She was the longest serving Prime Minister of the past century and was the first woman to take the role. In 1990 in the rank of the Prime Minister John Major has replaced her.

на всякий русский вариант
С 1945 года правящей партией и оппозицией были только две партии Консервативная и Лейбористская. В 80-е годы политикой Великобритании заправляла Маргарэт Тетчер,
которая была первой Премьер-министром женщиной и самой долгосрочным Премьер-министром прошлого столетия. В 1990 на посту Премьер-министра ее сменил Джон Мейнджер.