Police said at least 84 people, including 31 officers, were wounded and 201 arrested after anarchist groups splintered from the main union-led protest on Saturday and fought with riot police.
The clashes deflected attention from a peaceful rally to protest against public spending cuts, tax rises and pension reforms introduced by the Conservative-led coalition.
Cable said the government was listening to such concerns.
"But we are not going to change the basic economic strategy," he told BBC television.
"No government coalition, Labour or any other would change its fundamental economic policy simply in response to a demonstration of that kind."
The coalition is pushing ahead with a tough debt reduction programme to virtually eliminate a budget deficit, running at about 10 percent of GDP, by 2015.
Many European countries have seen protests in recent months as governments cut public spending to try to help their economies recover from the global financial crisis.
Britain's unions argue the government measures go too far, too fast and are economically unsound, putting future growth at risk, and are also causing misery to millions of ordinary people, with unemployment at its highest level since 1994.
But Cable said that cutting less or taking longer over it was not an option.
"When you do that the government has got to borrow more in order to finance this period and, as we know from what's happening in financial markets in Europe, it's actually very difficult for governments to borrow in these circumstances.