There is a risk in allowing the debate on teacher morale to dominate the education agenda. It can become a self-fulfilling prophecy and is hardly the best advert for attracting people into the profession. It can also leave too little space to promote the progress that is being made in our schools.

Yet the TES survey on the morale of school leaders conducted with the Association of School and College Leaders a few weeks ago (”‘Climate of fear’ eats the soul”, TES, 23 March) deserves attention for two key reasons. First, it shows that low teacher morale deters good teachers from taking on school leadership roles. The past few years have seen an impressive improvement in the quality of school leadership and we need more good people who are prepared to take on these responsibilities if schools are to meet the challenges they face. Second, although education will always, rightly, be subject to the pressures of rising expectations from the public and their representatives, some of the tensions it causes could be avoided.

There is no single cause of low morale. Poor leadership, unsupportive parents, inadequate buildings, badly behaved pupils, poor timetabling and a lack of professional development can all play a part - but politicians must shoulder some responsibility. Teachers usually criticise ministers for introducing too much change too quickly. Yet a constant demand for change and improvement is inevitable, so the debate must be about the way in which that change is best managed.

At the heart of the problem is the nature of the relationship between politics and education, which has undergone something of a revolution in the past three decades. A generation ago, politicians were more likely to promise the electorate new buildings or better equipment - all in their power to deliver. Now they promise higher standards, improved examination results and “no child left behind”. No matter how good the legislation, how fine the speeches or even how plentiful the resources, teachers are the only people who can deliver the higher standards pledged in election manifestos.

The working partnership between teachers and politicians is, therefore, more important than it has ever been. But it has become characterised by what divides the two, with little sense of any shared ambition. It is not just politicians who are impatient for higher standards; teachers want their pupils to do better, worry about the effects of poverty on attainment and aspire to achieve more. Most school leaders know how they compare with others and want to raise their game, and where teachers and schools underperform, there are few voices who would argue against action being taken to improve things.

So what gets in the way of a shared agenda and a common purpose? Inevitably, ministers have more than one audience. They are accountable to the public and other political parties are their competitors. Successive governments have tried to manage these relationships but, all too often, at the expense of that with the teaching profession. It is too easy to make enemies of teachers in order to make friends with the electorate.

It is, of course, the job of politicians to voice the aspirations of the public. They should always be cheerleaders for higher standards. They will always want to make the case for change; no one wins elections by arguing that things couldn’t be better. However, more so than in other public services, the way the case for change is made too often damages the relationship with those who deliver the service.

It is easier for politicians to build their arguments on a description of a failing service than an improving one. For all new governments, emphasising the weaknesses and underplaying the successes of their predecessors strengthens their argument for change and undermines their political opponents’ record at the same time. Being tough on teachers, intolerant of failure and demanding of schools shows that you are on the side of pupils and parents. The consequence is a teaching profession that can feel undervalued and isolated and a relationship that can become strained to breaking point.

It must be possible to argue for change and improvement without making enemies of teachers. Take two examples. First, the government proposals to further raise the floor targets and second, the new Ofsted inspection classification. Both reflect the best practice of teachers. Setting targets that build on previous best results is the bread and butter of effective classroom practice and I can only reflect on my own teaching experience and conclude that what used to be seen as good teaching would be considered fairly mediocre now. Standards are not static; they change over time as the profession builds on what works.

So why have these announcements damaged morale? In part, because they have been suddenly imposed and not developed as part of a professional, evidence-based discussion, but mainly because they are described as a response to a failing school system and not the development of an improving one. The government is able to “raise the bar” because progress has been made against previous targets. It is building on success. Yet policymakers seem compelled to claim it as a remedy for failure.

Of course, there is no room for complacency. Just as not all politicians are as good as the public might like, not all teachers are as good as they should be. Too many pupils don’t make the progress they could and nobody can be anything but frustrated about the continuing link between poverty and failure. However, we have more good teachers than we have ever had and schools are doing more to meet the challenges than ever before.

Somehow, in all this, it must be possible to create a policy environment that helps to move the standards agenda forward without lowering the morale of the only people who can deliver it.

Baroness Estelle Morris is a former education secretary and a former teacher.