Steelworkers from all over the country have demonstrated in Sheffield over cuts to Britain's ailing steel industry.
Thousands of job cuts have recently been announced in Teesside, Scunthorpe and Lanarkshire, with unions fearing more to come.
The TUC-organised rally urged the government to stem the influx of cheap steel from China.
Business Minister Anna Soubry said her department was doing all it could.
TUC general secretary Frances O'Grady said: "The crisis in British steel isn't over. One in six steelworkers face losing their jobs.
"Britain desperately needs a long-term industrial plan, but ministers have refused to commit to one.
"The closure of factories will devastate surrounding communities, and cause jobs losses throughout the supply chain. The chancellor's 'Northern Powerhouse' has to be more than a slogan for a party conference."
At the scene - Len Tingle, BBC Look North
The banners on the streets of Sheffield told the story as the march snaked through busy streets towards the city hall.
Angry steelworkers and their families have come from as far afield as Scotland, Wales, Teeside and Scunthorpe to add their voices to those from South Yorkshire.
They feel the government is standing aside as their their once mighty industry rapidly heads towards meltdown.
They blame Chinese dumping of steel on European markets for plummeting prices and high energy costs for making the UK industry uncompetitive.
The result has been the heartbreak hitting thousands of families as the consequent economic squeeze has led to the forced loss of plants and jobs in recent weeks.
And unions warn there is more to come unless action is taken now.
The Save Our Steel march was in part a protest over last month's announcement by Tata Steel that it is cutting 1,200 jobs at plants in Scunthorpe, Motherwell and Cambuslang.
Sarah Champion, MP for Rotherham, said the demonstration was a warning to ministers to help save the steel industry.
"Today's rally in Sheffield brought together steel workers, Labour MPs and unions from across the UK to try and make the government understand that unless it acts now, British steel has no future.
"We're not asking for a bailout, just a level playing field for British steel to compete on."
Rob Middlemiss, chairman of the Multi Union Tata Steel at Skinningrove in North Yorkshire, took part in the rally and said the scale of job losses would be devastating for communities.
"For every steelworker that loses their job, two or three more people lose it in the supply chain," he said.
"If there's 30,000 people left in steel, we're talking 100,000 affected, so the economy is those areas is going to be decimated."
Ms Soubry said the government was "working tirelessly" to help.
"It was the UK that helped persuade the European Commission to launch an investigation into steel rebar imports and the UK that secured an emergency EU council meeting this month," she said.
"We will continue to do all we can to achieve a level playing field for our steel industry and workers."