Online safety campaigner Baroness Kidron, another peer supporting the ban, said she worried the government’s consultation would become the “playground of the tech lobbyist”.
“The government has shown it will only act under pressure, not principle,” she added.
However, other peers urged caution about the proposal, with Labour peer Lord Knight of Weymouth arguing it could push teenagers towards “less regulated platforms”.
He added that a blanket ban would also deprive children of the more positive aspects of social media, adding that a better approach was to “listen to young people” during the government consultation.
Several charities and campaign groups, including the NSPCC, have said a full ban risks “unintended consequences,” and have called instead for stronger enforcement of existing child safety rules.
Asked earlier whether it would support the Lords’ amendment, Sir Keir Starmer’s spokesperson said: “Our position is clear. We won’t accept the amendment.
“This is an extremely complex issue. We believe the right thing to do is to gather the necessary evidence and insight before changing the law.”
The government consultation, which will run until the summer, will assess the merits of a ban for under-16s, as well as overnight curfews and actions to prevent “doom-scrolling”.
It will also look at whether more robust age checks could be implemented by social media firms, which could be forced to remove or limit features “which drive compulsive use of social media”.
The Liberal Democrats supported Lord Nash’s amendment after failing to win support for their own rival plan to restrict children’s social media use.
The party added that it would put pressure on the government to “come forward with concrete proposals for a workable plan”.
“While we may differ on the best approach, we believe there is a shared responsibility to act,” added education spokesperson Munira Wilson.
