A Chinese government minister apologised yesterday for half a century of relentless destruction of the nation's heritage, including much of the old city of Beijing.

Architectural historians and the United Nations' cultural organisation Unesco have criticised the impact of the rush to modernisation and Sun Jiazheng, the culture minister, said the government had broken its own laws in allowing redevelopment of its medieval heritage.

"Some cities have unilaterally gone all out to get a new look and have not done enough to protect old buildings,'' he said. He accepted that even areas of Beijing that were under official protection were being demolished. "There are things that I should have done and did not do, meetings I should have attended and did not attend,'' he said.

The century-long decline of the old city, once described by western aesthetes as a gem comparable to Paris, was exacerbated by the rule of Mao Tse-tung.

He put into practice his belief that the old had to be swept away before the new could be built by replacing the city walls with a ring road. But redevelopment has reached breakneck speed with economic modernisation.

According to some estimates, 600 hutongs - old alleyways - of Beijing's traditional grey brick, Ming and Qing dynasty courtyard housing have been demolished every year over the past decade to be replaced with apartment blocks and flashy high-rises. Campaigns by architectural historians have won support and promises from the government.

But the local government, which gains huge income from selling land-leases to property developers, has little incentive to administer the protection schemes they are ordered to put in place. Hua Xinmin, a leading campaigner for Beijing's old city said of the culture minister: "Protecting Beijing and attending meetings are two totally different things.

"He should just walk out and take a look at the old town - demolition is going on everywhere.''