The UK government has warned ISPs that it will introduce legislation in a bid to stop illegal downloads of music and films unless service providers can reach a voluntary solution.

Culture Secretary Andy Burnham said that consultation would begin in the spring and that any legislation could be in place "by April 2009".

Speaking before the unveiling of a creative industries strategy paper pledging to protect intellectual property, Burnham said that the move was a " clear signal" of the government's intention to tackle online piracy.

"Let me make it absolutely clear: this is a change of tone from the government. It is definitely serious legislative intent," he said.

"We will consult on legislation, recognising that there are practical questions and legitimate issues."

Burnham stressed that the government had "no burning desire to legislate", but warned that ISPs could prevent legislative action only by taking concrete steps to curb piracy.

Representatives of the recording industry, which blames piracy for a slump in CD and DVD sales, welcomed the proposals.

"ISPs are in a unique position to make a difference and to reverse a culture of creation-without-reward that has proved so damaging to the whole music community over the past few years," said John Kennedy, chairman of the International Federation of the Phonographic Industry.

However, industry watchers have questioned the logic of forcing ISPs to take action against individual users, predicting a switch in illegal download activity from the home to the workplace.

"If this legislation makes users liable for illegal content at home with the potential of having their internet access removed, it could drive them to carry out these activities in the safety and relative anonymity of the workplace," said a spokesperson for intelligent switching vendor ConSentry Networks.

"The implications are that the employer then becomes liable and could face having their broadband cut. Not forgetting the loss of productivity from the worker in the first place."