He is expected to say: "Britain is in a global race for jobs and wealth. Our infrastructure is decades out of date and we urgently need to invest and build.
The Prime Minister has tasked the new boss of HS2 with cutting costs, amid criticism from Labour that the project has a "black cheque".
The Prime Minister accused delayers of "betraying" those in the north who are most likely to benefit from the high-speed rail project.
"Those who want to delay or obstruct HS2 show a lack of vision. They are playing politics with Britain's prosperity. They are betraying everyone north of Watford. And they want to condemn Britain to the slow lane.
"We can either tell our grandchildren we made big, long-term decisions to build a better country... Or we can tell them we dithered for decades while the world raced ahead.
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The victim, who was wearing her uniform at the time, was found knocking on doors nearly four hours after she was abducted.
There will be gales across Scotland and northern England this morning, but these will gradually ease through the afternoon.
A 14-year-old boy was taken into custody following the attack in South Carolina in the US.