Ed Balls will express his commitment to HS2 today, but will reiterate that Labour's support for the project is "not at any cost".
He is expected to tell the annual Confederation of British Industry conference today: "Labour supports HS2 and the idea of a new North-South rail link because of capacity constraints on the existing rail network. But our support for it is not at any cost.
"The Labour Party cannot - and will not - give the government a blank cheque."
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United in grief, the people of Manchester have come together in defiance to the suicide bomber who killed 22 people on Monday evening.
Hashem Abedi, who was held in Tripoli on the same day his father was arrested, was planning terror in the Libyan city, officials have said.
A notably mild night, feeling close and stuffy.