Theresa May's most senior minister will warn Conservatives not to "keep calm and carry on" after their disastrous general election and instead "change hard" to win over young voters who backed Jeremy Corbyn's Labour.
Damian Green will tell Tories they must modernise after losing their House of Commons majority in an election in which they trailed anti-austerity Labour by 30 percentage points among voters aged 18 to 35.
He will address Bright Blue liberal conservative think-tank's conference in central London on Saturday as thousands are expected to gather a mile away for a "Tories out" anti-austerity demonstration, which Mr Corbyn is due to address.
It comes amid signals that the Government could ease off on austerity in response to the election result, but after confusion over whether it will review the 1% public sector pay cap.
The First Secretary of State will tell Conservatives to "listen to the complaints" of "excluded" voters and develop policies and a "distinctive" message that speaks to them, including a new "city Conservativism" to woo young metropolitan voters.
This will involve highlighting existing Tory policies to build 1.5 million homes by 2022 and the devolution of power to British cities.
Mr Green will say: "I first started writing pamphlets and making speeches saying the Conservative party needed to modernise in the late 1990s, when we had 165 MPs. Now we have 317.
"I am not standing here and saying all we need to do is keep calm and carry on. We need to think hard, work hard and change hard. We need to show how Conservative values and policies can work for those parts of the country, and parts of the population, who have turned away from us.
"It is now clear that the root of our failure to win a majority last month lies in those aged 18 to 35, among whom Labour led the Conservatives by over 30 percentage points.
"Modernisation in 2017 involves, as ever, listening to the complaints of those who are being excluded and developing both individual policies and an overall message which speaks to them. A country that works for everyone is Theresa May's ambition, and it is exactly what we need to aim for, as successful Conservative leaders have in the past.
"If we are to bring young, educated, working Britain back to the Conservative Party, we need to make a reality of the promise to build a country that works for everyone."
On housing, an issue now at the centre of the national conversation following the Grenfell Tower disaster, Mr Green will promise the Tories will build "high quality" homes, including social housing that creates "sustainable and integrated communities".
For renters, the Government will bring forward proposals to ban unfair tenant fees, encourage landlords to offer longer tenancies, and crack down on unfair practices in leasehold, such as escalating ground rents.
Mr Green will also highlight a failure to get "electoral credit" for creating metro-mayors and city deals to put large sums of money under more local control, because the Tories have failed to develop a clear message about why the party has done it.
He will call on the party to highlight the "essential Conservative principles" that decisions should be taken as locally as is practical, and that "only through individual flair and ideas and freedoms" does the "dynamism of a great city come to pass".