Bank of England governor Mervyn King on Tuesday said the eurozone crisis was his "biggest worry," while defending the bank's quantitative easing programs.

The central bank governor criticized EU leaders for failing to tackle the fundamental causes of the crisis and for adopting a policy of "kicking the can down the road."

The eurozone's failure to solve the long-running debt crisis had created a "great black cloud" of uncertainty for businesses all around the world, King said in an interview with BBC.

"The result is, until they know how this situation is going to be resolved, they are holding back from investment and spending," he said.

As a result, the problem was "getting bigger all the time," King said, adding that the biggest challenge facing the eurozone was "how to restore competitiveness."

King is concerned about the knock-on effect the crisis is having on the struggling British economy, which counts on Europe for about 50 percent of its trade.

He admitted that the central bank's policy of quantitative easing, which has pumped 325 billion pounds (503 billion U.S. dollars) so far into the British economy, had "not restored us to prosperity yet," but had at least prevented Britain from performing even worse.