Despite "the level of professionalism being better than ever", Ms Gilbert expressed concern that there was "widespread disillusionment in schools", leading to many talented teachers leaving the profession altogether, the Guardian reports.

"Recent surveys show terrible morale, so that is at rock bottom, but when I go into schools you do get real commitment, enthusiasm and so on," she commented. "I certainly think there is more room to celebrate what schools do and the really excellent work going on in so many of them nowadays but that doesn't make quite the same story as some of the other stuff. I started in the 1970s and I think teaching has never been better. I think teachers are far better, far more professional than when I started."

The comments from the former Ofsted Chief have come after the current Chief, Sir Michael Wilshaw issued a statement that "teachers don't know what stress is". In a response to Sir Michael Wilshaw, who said that difficult pupils, unsupportive families and the stress of the job was "too often used by staff facing the biggest challenges", Ms Gilbert said she believed "standards of teaching in the UK are excellent and teachers need to be celebrated more".

In a "collective crisis of confidence in the profession", NASUWT teachers' union revealed that nearly half of its 230,000 members have considered quitting in the last year. More than a third said that they did not believe they were respected as professionals and half said their job satisfaction had declined in the last year.

Commenting on stress within the teaching profession, Julian Stanley, Group Chief Executive of Teacher Support Network, said: "Is it any wonder that teachers' morale is at "rock bottom", as former Ofsted Chief Inspector Christine Gilbert suggests? Barely a day seems to go by, at the moment, without some comment appearing about the teaching profession. Whilst some are positive, the majority attack the profession, sending out a negative message to the public that it is "okay" to criticise education staff."

"The recent comments from Sir Michael Wilshaw, the Chief Inspector of Ofsted that "teachers don't know what stress is" are a case in point."

"The truth is that many teachers are stressed. Indeed it is likely that most teachers in the course of a long career will experience stress that is non-productive. For some it will deeply impact on their professional and personal lives. Like it or not teaching, though a deeply rewarding profession, can also be very challenging. To suggest otherwise flies in the face of the reality expressed by thousands in the profession."

"Teacher Support Network is the only independent charity providing emotional and practical support to all teachers. In 2010 and 2011, we received nearly 5,000 calls and emails from teachers who were suffering from anxiety. 4,256 teachers indicated they had a low mood when contacting us, while 3,293 felt overwhelmed. This is just the tip of the iceberg. We estimate that as many as 40,000 teachers could be struggling with anxiety, depression or stress. Excessive workload, poor behaviour and issues about bullying in the workplace are frequently cited as the prime contributors in the development of poor health and anxiety. They come at a cost to the individual and the taxpayer in terms of sickness absence, health problem, which the NHS then has to treat. In addition prolonged stress often has a very negative impact on self-esteem, family life and relationships."

"We must listen more to teachers at the chalk face, and to those headteachers, teaching unions and others directly involved in education to truly understand the impact of low morale, stress and depression, not only on teachers, but also on their pupils."

"Teachers are not whingeing; they are expressing genuine concern and they should not be made to feel fearful or at risk of being singled out as poor teachers simply because they express their vulnerability when the going gets tough. Asking for support is a sign of strength and investing and supporting the workforce is a core principle of effective management."

"It is time to celebrate the teaching profession - the vast majority of whom are deeply committed and do an excellent job day in day out."

"How else will we attract, and just as importantly retain, the best candidates to teach our children?"