Peers have defeated the Government by backing the resurrection of the Leveson inquiry into press behaviour by 252 votes to 213, majority 39.
The move puts the unelected chamber on course for a constitutional clash with the Commons, which had previously rejected a demand for a further investigation into the relationship between the media and police.
The amendment would force the Government to establish a new inquiry into allegations of data protection breaches by national news publishers.
Analysis of the division list showed three Conservative rebels supported the amendment.
They were former ministers Lord Blencathra and Baroness Warsi and former frontbench spokesman Earl Attlee.
Culture Secretary Matt Hancock said: “I’m disappointed that the House of Lords have again voted against press freedoms.
“In the Commons we proposed forward-looking action to ensure a free, fair and responsible press. The Lords’ amendment is unnecessary and we will seek to overturn it.”