Applications to be excused from jury service should be dealt with "sensitively and sympathetically", judges have been told.
Guidelines handed down in London by the Lord Chief Justice acknowledged changes to the law in April last year which have meant an increase in the number of jurors with professional and public- service commitments.
Around 480,000 people are summoned for jury service annually and previously less than half, around 200,000, were eligible.
Now, virtually every adult - including judges, barristers, solicitors, court staff, police officers, MPs and doctors - must serve if summoned.
Only two categories are still exempt - those with a mental illness and those convicted of a criminal offence. In updated advice, which comes into effect on April 4, Lord Woolf said that trial judges must continue to be alert to the need to exercise their discretion to adjourn a trial, excuse or discharge a juror - should the need arise.
He said that a judge must use common sense and discretion according to the interests of justice when faced with a juror who unexpectedly found him or herself in professional or personal difficulties.
"This might apply, for example, to a parent whose childcare arrangements unexpectedly fail or a worker, who is engaged in the provision of services the need for which can be critical, or Member of Parliament who has deferred their jury service to an apparently more convenient time, but is unexpectedly called back to work for a very important reason."
He added: "The good administration of justice depends on the cooperation of jurors who perform an essential public service. All applications for excusal should be dealt with sensitively and sympathetically and the trial judge should always seek to meet the interests of justice without unduly inconveniencing any juror.