"The problem is if all the big countries in Europe cut spending at the same time it is very difficult to see where the extra sources of demand are going to come from to sustain growth," said Carlin.

Just a mile from the bustle of London's financial district lies Borough Market. Among the pricey food and drink stalls, Michele Marconi arranges the exotic blooms at her flower shop, Chez Michele. They are the type of luxury item that are vulnerable in a downturn, and which now face an increase in sales tax to 20 percent. Michele takes a philosophical viewpoint.

"In my position I cannot do a lot, I just have to follow what happens," said Marconi. "They are probably going to buy less flowers, but I think if you still maintain quality your customers will always come back."

Such optimism is reflected in the general public. A recent poll showed 59 percent of British people support the government's spending cuts. Its message about the danger of the debt appears to be getting through.

But the full effects of the cuts will only be felt in the coming years. More protests like this seem certain as British society faces it biggest transformation in a generation.