Journalists who pay witnesses involved in criminal trials could face jail under tough new rules unveiled by the lord chancellor on Tuesday.

The new rules were announced following several high-profile trials where witnesses had admitted to accepting money from national newspapers before giving evidence.

The recent case of schoolteacher Amy Gehring, as well as the trials of Rosemary West and Gary Glitter, had all raised concerns that the statements of witnesses were being influenced by "chequebook journalism".

Baroness Scotland of Asthal said a "worrying dependency" was developing and that the press code was not working as well as it should.

"We all have a civic public duty to perform to ensure that justice is done. Payments to witnesses during a trial is not a good thing," said the parliamentary secretary to the Lord Chancellor's Department.

"People when they come to give evidence can be honestly relied upon to tell the truth not because they have been paid but because they are telling the truth. We are dealing with the integrity of the trial process," she said.

The acting chairman of the Press Complaints Commission, Professor Robert Pinker, said the new legislation must not restrict press freedom.

"We will study the points made in the lord chancellor's consultation paper with interest and respond constructively to them." he said.

"The lord chancellor is of course right to be concerned about the administration of justice - the proper functioning of which is a crucial element in a free and democratic society.

"But there will continue to be an important argument about how best justice can be protected especially where legislative proposals impinge on press freedom and public interest."