Workers have staged a public protest accusing Chancellor Gordon Brown of failing to protect victims of collapsed occupational company pension schemes.
Thousands of people across the UK have lost their pensions
Demonstrators in Cardiff unveiled a billboard claiming he "destroyed" the pensions of 125,000 UK workers.
The government has expanded the Financial Assistance Scheme by £6bn, but campaigners say it is not enough.
Ex-Allied Steel and Wire (ASW) workers from Cardiff and Sheerness, Kent, who lost pensions attended the unveiling.
About 1,000 ASW workers lost their jobs and their pensions when the company was declared bankrupt in 2002.
Despite taking their case to the European Court of Justice, they failed in their bid to force the government to make up the shortfall.
European judges said pension rules were "inadequate" but it was up to British courts to decide if the government had to pay out.
Unions claimed the government had failed to protect the workers, including the scrapping of pension tax relief.
The move deprived pension schemes of around £5bn a year of funding, adding to the "black hole" caused by regulatory pressures, stock market failure and increased longevity of scheme members.
Ministers have also been attacked by campaigners for refusing to accept findings by parliamentary ombudsman Ann Abraham, who said the government was guilty of maladministration and urged that victims be compensated.
THE LOST PENSIONS
85,000 people were affected
400 schemes closed with deficits
They were shut between 1997 and 2005
Only limited compensation is available from the Financial Assistance Scheme
The Pension Protection Fund only covers schemes from April 2005
But ministers said they would not use public money for compensation.
However, in February, four people who lost all or part of their company pensions won their High Court case against the government.
The court ruled that the government was wrong to completely reject the ombudsman's report into collapsed pension schemes.
The court decision does not oblige the government to compensate an estimated 85,000 people for their loss.
As part of the protest, the billboard has been erected in central showing Mr Brown wearing a Teddy Boy suit stamping on the ombudsman's report and squashing Labour's red rose.
The slogan "Labour lets Gordon Brown destroy workers' pensions" is also included and the names of the seven companies whose pensions schemes have failed since Labour came to power - including ASW's - are shown dropping from the rose in Mr Brown's hand.
Many workers who have lost their pensions face a poor future
Ros Altmann, pensions campaigner and former Downing Street adviser, said: "It is now clear that Gordon Brown had no information at all on what his raid on pension tax credits would do to smaller company pension schemes. He only had information on the very largest companies.
"He made no attempt to help workers who lost out as a result of his tax raid and instead focused on giving money to big business in tax cuts in order to help long-term growth."
John Benson, one of the workers from Cardiff who lost his £11,000-a-year pension when ASW went bust added: "We have lost our pensions through government incompetence and the man responsible is Gordon Brown.
"I voted for Labour all my life, for 40 years, and I am ashamed at what they are doing. They are letting Gordon Brown do whatever he wants.
"It is a total disgrace. Families have been destroyed."
"He has destroyed the finest occupational pension system in Europe and turned it into the worst," said Mr Benson.
The poster, funded by the Pensions Action Group, will remain in place for a month and an identical one is being unveiled in Scotland.