Thousands of workers from across the UK have joined the traditional May Day trade union rally in central London.
Demonstrators marched to a rally in Trafalgar Square
TUC chief Brendan Barber called for strong laws to tackle poverty pay, the gender wage gap and work discrimination against ethnic minorities.
Speeches in Trafalgar Square followed a march from Clerkenwell Green.
Workers from the Peugeot factory in Ryton, near Coventry, which is to close in July with the loss of 2,300 jobs, took part in the demonstration.
Mr Barber told the rally: "No longer should British workers like the Peugeot workers in Coventry find that they are the cheapest and easiest in Europe to get rid of when the going gets tough - and we send them a message of solidarity today."
He added: "We need stronger unions allowed by law to give workers a powerful voice at work, supporting each other in solidarity.
"That's why we called for a Trade Union Freedom Bill to allow unions to properly protect their members."
Amicus general secretary Derek Simpson said the government faced "disastrous defeat" at the next general election unless it addressed concerns over NHS cuts, job insecurity and pensions.
"The sooner this government learns some humility, starts listening to ordinary people, does something about employment laws, does something about pensions, does something to protect industry, then this demonstration would have served its purpose," he said.
The march was organised by the TUC and the London May Day organising committee.
The traditional event brings together trade unions, anti-globalisation organisations, migrant workers, pensioners and other campaigning bodies.
In 2000, anarchists ran riot and defaced the Cenotaph in Whitehall in protests which took place at the same time as the TUC march.
But in recent years there has been little trouble.
Last year, up to 40,000 took part in the demonstration which ended with a music festival and speeches in Trafalgar Square.