Crown courts in England and Wales could be closed down by a lawyer strike.
Criminal barristers are in a stand-off with ministers over funding, and point to numerous exits from the profession and general pessimism about the state of the sector.
The Criminal Bar Association is to ballot members after a survey last month showed 94% of criminal barristers who responded wanted an undertaking by the Secretary of State for Justice Dominic Raab that he would provide his full response to a recent the legal aid review and complete any consultation process by the end of March.
"The deadline has now passed and we have received no undertaking. Following a meeting of the CBA executive this evening it has therefore been resolved that we will now proceed to a ballot for action to be issued on 28 February," said chair Jo Sidhu Q
A strike action could see thousands of trials delayed.
Last month an independent review said the legal aid budget needed £135m to reverse a huge exit of lawyers.
Deputy prime Minister Dominic Raab (pictured) said he will respond by the end of March.
The £1bn criminal legal aid system pays for both solicitors and barristers but lawyers say that slashed resource have effectively cut their pay.
Some barristers say that they now earn less than the minimum wage, based on hours worked.