More than 100,000 people have signed Labour's petition to make British homes safe in light of the Grenfell Tower disaster.
The petition urges the Government to retrofit sprinklers in tower blocks, using public money.
Labour MPs Peter Dowd and Andrew Gwynne have handed the petition to the Treasury, just hours before the Budget is announced.
Gwynne posted a picture of campaigners outside the Treasury building on social media, saying he hopes the Government will listen to their concerns in the Budget.
The campaign is a personal success for Labour leader Jeremy Corbyn, who has played a leading role in the sprinkler campaign.
Corbyn has spoken out regularly on the issue, urging the Government to set aside an extra £1 billion to equip all tower blocks with sprinklers. He has claimed only 2% of council and housing association tower blocks have sprinkler systems, and suggested the Government is failing to learn the lessons of Grenfell.
Seventy-one people died when a huge fire engulfed Grenfell Tower in June, ripping through the building within minutes.
Paul Atkins, a fire safety expert who previously worked on Grenfell, has told the BBC that sprinklers would have prevented the fire from spreading.