Mr Carlile's 15-year-old daughter, Ruth, has been seriously ill for nearly two years with clinical depression, but that has become acute in the past few months and she is now an in-patient at a psychiatric hospital. Mr Carlile said that many MPs encountered stress in dealing with family life and careers at Westminster. "Ruth and I are very close. There has to be more than a biological relationship," he said.
His daughter's need for her father to be around more often, even if it means giving up his career, will strike a chord in the homes of many MPs. Some Labour frontbenchers are concerned at the extent to which they have been away from home while their children have grown up in northern constituencies.
"It is clear to me that I can play an important part in Ruth's eventual recovery but only if I am more a part of Ruth's life than my activities as an MP have enabled me to be," Mr Carlile said. The MP for Montgomery, in Powys, who has a 5,209 majority, took the unusual step of appearing at a Westminster press conference with his wife, Frances, to announce the reason for his decision to step down within months of a pending general election.
Mrs Carlile said: "This has been a stressful and difficult decision for Alex. He is a person of strong loyalties - to his constituents, his party and to his family.
"It has taken us all some time to adjust to the extremely slow pace of recovery from mental illness and the time needed to help Ruth. He just wants to be there for her."
As leader of the Liberal Democrats in Wales, Mr Carlile said he was away from home "an awful lot". "There have been huge numbers of occasions when I have arrived home when my daughter has been asleep in bed and I have left before she got up in the morning."
The Jopling report tried to tackle the problem of the stress on MPs' families by reducing the number of late-night sittings and allowing MPs to have more long weekends by scrapping sittings on many Fridays.
The reform of MPs' hours was given a boost by the resignation from Margaret Thatcher's Cabinet of Sir Norman Fowler, to spend more time with his family. He later helped to run John Major's general election campaign but never returned to office.Reuse content