Getty Boris Johnson and Nigel Farage are leading the battle to leave the EU

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What is purdah? Purdah is an official period that, in this instance, covers the final four weeks in the run up to the EU referendum. It began on Friday May 27. During purdah, civil servants must not provide information on the referendum that could sway the public and influence the way that they vote. Central Government and local authorities are now banned from publishing material related to the referendum and Brexit debate.

The Cabinet Manual says British governments must also “observe discretion in initiating any new action of a continuing or long-term character in the period immediately preceding an election”. But it adds that “essential business must be allowed to continue”.

What will happen during purdah? The start of purdah means that the Treasury can no longer publish dire warnings on what might happen if we leave the EU. The Government’s barrage of scaremongering predictions will finally end to the relief of Eurosceptics and Brexit campaigners. Purdah will now prevent the Remain campaign from giving itself an unfair advantage by using the civil service. For example, the Government cannot send out any more leaflets telling voters why it believes that voting to remain in the EU is the best decision.

12 reasons why you should vote IN or OUT of EU Tue, May 10, 2016 We take a look through 12 reasons you should vote IN or OUT of the EU as Britain decides on June 23rd 2016. Play slideshow Getty 1 of 13 12 reasons why you should vote IN or OUT of EU

Where does the word purdah come from? It refers to the Muslim and Hindu practice of screening women from men, often using a curtain. It has been used in a political context here since the early 20th Century.