Meaning of purdah and why bills are stuck in 'wash-up'

Parliament was expected to wind up yesterday after Rishi Sunak stunned Westminster by calling a snap general election for 4 July. The Commons is dissolved after an election is called and the official closure date for this election will be 30 May. After this date, MPs lose their jobs and either decide to leave politics, campaign for re-election in their constituency or run for a different seat.

- KATE DEVLIN, MATT MATHERS

What is parliamentary 'wash-up' 

No government business is conducted after parliament is prorogued and dissolved but the civil service continues to work under strict purdah rules while election campaigning takes place. The word "purdah" is derived from the Urdu and Persian word "parda" meaning "veil or curtain" and often refers to the practice in certain Muslim and Hindu societies of screening women from men or strangers, especially by means of a curtain.

However, at some stage in the early 20th century it was appropriated and used in a political context. After an election is called, the government must decide which bills it wants to prioritise passing before parliament is prorogued - a process known as the "wash-up" period. The process can involve talks between the government and opposition parties to get their cooperation to pass some bills.