Former Thomas Cook workers have staged noisy protests outside the UK Business Department amid claims they were "abandoned" by the British Government.
They handed in petitions to 10 Downing Street and the Business Department, calling for a full inquiry into the travel giant's collapse and for the company's directors to pay back their bonuses.
They expressed anger at the way they found out about the company's demise, and called on UK Business Secretary Andrea Leadsom to make sure they receive their unpaid wages.
They were not paid their monthly wages on Monday, and many said they were having problems with rent and mortgage payments, and were having to borrow money from friends and family.
Scores of workers travelled from across the country to join the protests, holding up banners which read Pay Up and Never Again.
Martin Brown, who worked as a cabin crew manager for Thomas Cook based in Manchester, said: "It is disgraceful that a company of this size has been allowed to fail because of Government apathy.
"The airline side of the business was profitable, so how could it fold? It is disgraceful. I'm having to borrow money from a friend because I haven't been paid," said Mr Brown, who worked for Thomas Cook for 21 years.
He added that he believed the company could have been saved if UK Parliament had not been prorogued, denying MPs the chance to force the Government to intervene.
Gurprit Kaur, a cabin crew member based at East Midlands Airport, said: "We want to know why this company was left to go out of business, and why the bosses paid themselves so much money, so we can stop this happening again in the future.
"I had come back from a flight and was due to work the following day when I was woken up in the middle of the night by a message telling me not to report for duty.
"The Government should have put procedures in place so this could not happen."
Unite's assistant general secretary Diana Holland said: "The fact that workers are coming to Parliament from all parts of the UK demonstrates just how angry workers are with the Government, which they rightly believe has abandoned them.
"This week, workers have been left with no income as their wages were not paid.
"Workers do not understand how the profitable Thomas Cook airline was allowed to collapse while the European subsidiaries were able to continue to fly.
"The very least the Thomas Cook workers deserve is to receive an answer to the question as to why the company was allowed to collapse, as well as an explanation from the Government as to its lack of action in the lead-up."
Manuel Cortes, leader of the Transport Salaried Staffs' Association (TSSA) UK, said the Government must ensure that workers are paid what they are owed in full and without delay.
"This means for the work carried out to the point at which the company went bust, but also redundancy payments and any other entitlements.
"I will be telling ministers and everyone else at the task force meeting: the choice is simple - pay up or be sued."
The TSSA has agreed to make a payment of £300 (€330) to each of its Thomas Cook members from the union's benevolent fund.
UK Labour leader Jeremy Corbyn met the Thomas Cook workers outside Parliament, saying: "Today we showed support for the Thomas Cook workers who've done an incredible job with their company over many years.
"They've showed real responsibility when the company collapsed to make sure that the passengers got home.
"The Government, on the other hand, stood idly by, watched the company collapse and did nothing about the incredible payments that were made, the bonuses to directors and managers of the company, while the workers lost their jobs and lost their wages.
"So even now we're demanding the Government intervene to make sure this company survives. It is a viable business, it is a valuable business, and an iconic name in the travel industry."
Mr Corbyn said something should be done about the wages of the chief executive, especially considering how uncertain things are for the former employees.
"I think the workers here have given a very clear message that they have been treated abominably, they've lost their jobs, they've lost their income while the directors have walked away with massive bonuses.
"Maybe those directors as an act of conscience should recognise the hurt the workers feel. They're after all the ones who made the company what it is.
"It's a great name and I want to see it flying again."