Labour would part-nationalise BT to deliver the policy and tax tech giants to help cover the £20bn cost.
A reduction in business rates for small firms is among a raft of measures pledged by the Conservatives.
Sir Ed Davey will promise to "jump-start" efforts to tackle the "climate emergency" in a speech on Friday.
The Conservative Party has denied offering Brexit Party candidates jobs or peerages to stand down.
The Labour leader will not say whether he wants the number of people coming into the UK to rise or fall.