The business secretary said the coalition was "one of the strongest governments" the country had ever had, dealing with a financial crisis.
The TUC said 250,000-500,000 people attended the anti-cuts march in London.
It condemned violence which broke out alongside the protest, leading to 201 arrests. Two people have been charged.
Of those arrested 199 were still in custody on Sunday afternoon, the Metropolitan Police said.
The Met said 145 of the arrests were in connection with a demonstration by campaigners UK Uncut, which occupied luxury grocery store Fortnum & Mason in Piccadilly in protest over alleged tax avoidance by the business's part owners.
The force has faced some criticism of the way it handled the protest, with former Met Deputy Assistant Commissioner Brian Paddick saying officers should have done more to protect property.
But London's deputy mayor Kit Malthouse said officers had a "difficult balance" to strike between policing the main demonstration and unrelated incidents of violence including attacks by anarchist groups.
The two men charged have been released on bail ahead of court appearances.
A 17-year-old from Manchester has been accused of possession of an offensive weapon and going equipped for criminal damage, and a 31-year-old from Glasgow has been charged with violent disorder and assault on police.
