David Cameron’s government is to spend £9 million delivering a leaflet on why voters should back the European Union to every house in the UK.

More than half a million pounds was spent on printing the glossy booklets alone.

Another £2.5m will go on ‘digital promotion’ and a website, while just under £6m will be spent on postage and packaging.

The leaflets will start dropping through letterboxes up and down the country from next week.

Ministers defended the spending saying that research showed that 85 per cent of the public wanted more information to help them make up their minds.

But it is likely to draw howls of protest from Leave campaigners.

The leaflet has been produced before the elections watchdog brings in strict spending limits.

The Electoral Commission will also send a leaflet to every household, a page of which will be given over to both the Leave and Remain campaigns.

No 10 pointed to precedents including the 1975 EU referendum, the 1997 Scottish Parliament referendum and the 2014 Scottish independence vote, where the Westminster Government had also sent leaflets to every home.

Ministers insisted that the total cost this time around was only 34p for every household in the UK.

The Conservative Environment Secretary, Liz Truss, said that the referendum would be a” huge decision... perhaps the biggest we will make in our lifetimes,”

She said that the document “makes clear why EU membership brings economic security, peace and stability. It also sets out that if the UK voted to leave, the resulting economic shock would put pressure on the value of the pound, which would risk higher prices of some household goods.”

The government has also launched a website www.eureferendum.gov.uk designed to provide further information.