Imagine you have arrived in Uzbekistan. You have no money to speak of and don’t speak the language. You don’t recognise the alphabet and you don’t understand much about locally approved ways of interacting socially. You know you are there for the long haul. You need to find a doctor, sort out schooling for your children, negotiate the local shops. The situation is no different for many migrants to Britain.

English for speakers of other languages (ESOL) addresses that need. It engages with adults’ experiences of moving to the UK and with the interaction between migrant and settled communities in terms of expectations and customs. It directly addresses two key policy concerns that have challenged successive governments: how to eradicate poverty and how to secure community cohesion in a society with high levels of mobility.

ESOL has always been an arena fought over by politicians, and in England it is too often a story of moral and policy failure by government, ameliorated by the passion and professionalism of practitioners. Yet no other area of lifelong learning provision has a more positive impact on the life chances of Britain’s poorest settled communities than ESOL. Study after study shows that the lowest levels of participation in education and training after school are among women from communities of Bangladeshi, Pakistani and Somali heritage, who are among Britain’s poorest people.

Weak or non-existent English language skills and a lack of formal qualifications limit opportunities and hold back productivity in the wider economy. The ability to speak English effectively is essential in getting work that makes use of your skills. It is needed to support your children at school, to play an active part in the wider community - in short, to join David Cameron’s “big society”.

But the value of ESOL is also seen in the workplace, releasing the skills of the highly qualified and experienced migrants on whom so much of the NHS and the care sector depend, and it is seen in the dynamic entrepreneurialism and innovation that second-language speakers bring to the wider economy.

Strengthening the English language skills of workers makes good economic sense. This was recognised in the 1970s, when Industrial Language Training Units combined the teaching of language in a work context with embedding cross-cultural understanding for employers and employees, migrants and established citizens alike.

Then, after more than a decade of policy neglect, we rediscovered ESOL’s importance. The launch of the Skills for Life strategy in 2001 expanded public support for ESOL classes. Participation soared, particularly among people whose English was weakest. Pressure on class places intensified with the arrival of large numbers of European Union workers. By 2005-06, ESOL student numbers and budgets had tripled; two-thirds were women and nearly half of all students were pursuing entry-level courses. Yet waiting lists in the cities were still significant, especially in London.

Then things suddenly changed. The major reversal of funding policy that flowed from the 2003 skills strategy, and its annual successors, hit ESOL provision. Money was systematically removed from freely elected course provision for adults over 24 to the wholly misguided Train to Gain programme, which taught employers that the state pays for training. Then the government ended all public funding for ESOL in the workplace. The result has been a reduction in participation and investment of almost 70 per cent from the peak years.

Meanwhile, the 2011 census reports that 850,000 people cannot speak English well or at all, and among the 200,000-250,000 people expected to migrate to the UK annually a majority will use English as a second or additional language. Meeting the needs of these groups presents a real challenge to government. Yet unlike Wales or Scotland, England lacks a national strategy for ESOL.

Why has this happened?

As a society, we seem to hold in tension two contradictory views about migration. On the one hand, Britain has seen itself as tolerant, open, just and a beacon of democracy for Huguenot, Jewish, Polish and Irish peoples as well as later waves of immigration - the happy recipient of the exceptional skills of migrating scientists, artists or footballers.

Yet a disturbing and deeply disagreeable underbelly in British polity blames foreigners for their foreignness and fails to recognise how diversity enriches our lives. From Enoch Powell’s 1968 “rivers of blood” speech onwards, this has been shockingly evident, fuelled by the Daily Mail and the Daily Express, and by the distortions and exaggerations of the thinktank Migration Watch.

This strain of thinking was surely behind the introduction of a rule that denied adult asylum seekers access to publicly funded ESOL courses until their asylum status was confirmed, or until six months had passed. Of course, after six months, asylum seekers will inevitably have found ways of getting by without the language - they are often vulnerable to exploitation by others, reliant on their children for interpretation and, crucially, settling into a parallel linguistic universe.

Denying language to vulnerable, traumatised people starts from a presumption that the applicant will not be entitled to the care and support we promise in our international treaties to people fleeing injustice, violence and tyranny - and it feeds community tensions.

There is no doubt that change and difference can be unsettling, and we need to recognise that community cohesion is fostered by attending to the needs of marginalised settled communities, as well as those of linguistic minorities. The Commission on Integration and Cohesion and the Cantle report show that community tensions are greatest when people lead parallel lives and do not build trust through day-to-day interaction.

Investing in ESOL helps governments to overcome that isolation and better manage an open society operating in a globalised world, where anxious and xenophobic introversion persists.

What is to be done?

In its report On Speaking Terms, thinktank Demos calls on all political parties to include in their manifestos for the 2015 general election a commitment to a national strategy for ESOL, which recognises the wider social policy impact of language skills alongside the current exclusive focus on employability.

In my view, a national strategy needs to secure an increase in provision, to secure its quality and to strengthen infrastructure. On provision, it would really help to have a learning entitlement for language learners up to level 1, language and cultural orientation for new arrivals - as in Germany or Sweden - and matching employer investment in ESOL.

To secure quality, we need regulations insisting on qualified teachers, an expanded teacher supply, support from a national centre of expertise, and stronger mentoring and language teaching support work using linguistic minority staff.

On infrastructure, we must revitalise mechanisms for recognising overseas qualifications and experience, to prevent linguistic migrants wasting themselves in jobs below their level of competence. In addition, we should establish local ESOL strategy boards, reintroduce translation facilities, introduce personal learning accounts and strengthen information, advice and guidance services.

Finally, we need to complement a national ESOL strategy with a national community cohesion strategy targeting the full range of England’s communities. This should be coupled with a national foreign language strategy to encourage more of us to learn other languages, since British people’s weakness at learning other languages hurts us both economically and culturally. Above all, we need the political will to recognise the importance of investing in ESOL to include everyone in our democracy.

This is an edited version of the 2014 Chris Taylor Memorial Lecture. Alan Tuckett is president of the International Council for Adult Education, a governor of Cornwall College and former chief executive of Niace