California is to allow lawyers to whistleblow on clients for the first time as it prepares to implement new conduct rules that will bring the notoriously strict state in line with most US bars.

The new rules, which come into force on 1 July, will for the first time allow Californian lawyers the right to breach client confidentiality in order to “prevent a criminal act that the attorney reasonably believes is likely to result in death or substantial bodily harm”.