On 15 February 1971 Enoch Powell stood up to speak at the Carshalton and Banstead young Conservatives club in Surrey. It was three years since the Tory MP had made his incendiary "Rivers of Blood" speech; now he was returning to the subject of immigration and he was, again, in apocalyptic mood. Mass immigration had, Powell claimed, led to the native British seeing their towns "changed, their native places turned into foreign lands, and themselves displaced as if by a systematic colonisation". Powell's natural constituency was those white British people who were disenchanted by immigration, but, inevitably, he was also a substantial figure in the lives of immigrants. Ayub Khan-Din was 10 years old in 1971, the youngest of 10 children born to a Pakistani father and white British mother living in Salford. In his play and screenplay East Is East – it was first staged in 1996 and became a highly successful film three years later – Powell makes cameo appearances: on TV talking about repatriation and on posters advertising an appearance at Salford town hall.

Powell was concerned with the impact of immigration on the native British; East Is East explores the impact that arriving in a new country had on the immigrants and their children. Khan-Din's script describes a personal sense of dislocation and a struggle for identity in the face of a father determined to remind him that he is Pakistani. From today it is being restaged, with Khan-Din playing George and Jane Horrocks as Ella. The play and film revolve around George Khan (played in the film and original stage production by Om Puri), a Pakistani married to Ella, played by Linda Bassett, with whom he has seven children. George and Ella run a fish-and-chip shop in Salford and he is determined to raise his children as traditional Pakistani Muslims; they feel more British than Pakistani and ultimately rebel against him.

For Khan-Din's family, and those like them, Britain in the early 70s was often unwelcoming; it was a time of tin baths and "Paki-bashing". The prospect of repatriation still seemed plausible and the presence of Asian immigrants in the media was limited to a specially commissioned Sunday morning BBC TV show. I was born in Pakistan in the year East Is East is set and came to Britain three years later; as a small boy I remember my father warning us that our time in Britain could be summarily cut short. This was the one thing that united Powell and men like my father and George Khan: they all hoped that one day the immigrants would return "home".

That may have been a necessary delusion, but it was one that his children could not share. Khan-Din started writing East Is East fewer than 10 years after it is set, while his father was still alive. The play reads as though it was written from a place of anger – the anger of a young man trying to understand his father, and of a writer working through his confusion about what it means to be both white and Pakistani. Khan-Din has admitted that for a long time he felt alienated from his Asian side. He hated walking down the street with his father because he was embarrassed at the way they would be treated. The alienation is there in the text. George calls his children "bastard", while they call him a "Paki" and joke that perhaps Powell could repatriate him; George beats his wife and rules his family like a despot.

There are also moments of tenderness and amusement, but on stage and screen it can come across as something like revenge. George is an outsider twice over: not fully inside the Pakistani community and not fully accepted by his white neighbours. He wants his children to behave as he did not: to marry Pakistanis, though he left his Pakistani wife for a white woman. In his speech in Surrey, Powell had warned that "the explosive that will blow us asunder is there and the fuse is burning but the fuse is shorter than had been supposed". It was a sentiment with which George Khan may well have agreed.

"The indigenous population often feel themselves to be strangers in their own land; they see their pubs, their shops, and their streets taken over. Then if they complain they are called racist." This was not Powell in 1971 but Nicholas Budgen, the Conservative MP for what had been Powell's constituency, in an article published on 18 March 1997. Budgen's words were a reminder that while much had changed in Britain in the intervening quarter century, unease about immigrants persisted. The article was published one week before East Is East made its London stage debut at the Royal Court. Khan-Din's play was set in a time when British Asians were near-invisible, but by the time it reached the stage they seemed to be everywhere. The comedy sketch show Goodness Gracious Me had begun on radio the previous year and would soon transfer to television. Gurinder Chadha's film Bhaji on the Beach had been released three years earlier and Hanif Kureishi, another mixed-race British-Pakistani son of the 70s, was an established novelist and screenwriter. Khan-Din had acted in 1985's My Beautiful Laundrette; Kureishi's semi-autobiographical The Buddha of Suburbia had been broadcast two years earlier and the film adaptation of his story My Son, The Fanatic was released in the same year East Is East reached London. The band Cornershop released "A Brimful of Asha", which, in the following year, 1998, would reach No 1. I have a vivid memory of standing in the middle of a nightclub around that time watching young white men and women dancing Indian‑style to the song. There was a palpable sense that being Asian was, to the outside world at least, no longer synonymous with being tortured and uncool; things had moved on – the script had changed.

I saw the screen version of East Is East at a Luton cinema in November 1999, during the first week it was released. I was 28 years old, working for Channel 4 News and living in London. Despite a less than promising start, life was, in the main, working out well for me. To watch East Is East back in my hometown, surrounded by other young Asians, was a powerful experience. The film had been marketed as a comedy, but for all its moments of humour both black and broad, I thought it was at heart a tragedy. It was tragic to be reminded of the racism that George and his family faced, but even sadder were the ways in which things had not progressed for young Pakistanis. The scene where George's son Nazir meets his bride on their wedding day, and then flees because he cannot abide the idea of marrying someone he does not know, was watched in silence in that cinema because we knew that one day that could be us. Watching East Is East was to be reminded how far we had come, and how far we still had to go.

"In scores of our cities and market towns, this country in a short space of time has, frankly, become unrecognisable. In many parts of England you don't hear English spoken any more. This is not the kind of community we want to leave to our children and grandchildren." This was not Powell in 1971, or Budgen in 1997, but Nigel Farage, leader of Ukip, speaking at his party conference in February 2014. The latest production of East Is East comes at a time when Farage and his party are profiting from a renewed apprehension about multiculturalism and immigration. The years since the first staging of East Is East have been scarred by 9/11 and 7/7, and seen a rise in religious identity. George Khan was proud to be Pakistani; today's young British Pakistanis are more likely to express loyalty towards their faith. In the 70s, Asians were perceived as hard-working but docile; they were the victims. Today the perception has changed. The British Pakistanis who sexually abused children in Rotherham, Oxford, High Wycombe and elsewhere are only a tiny part of the community, just as those who have travelled to Syria and Iraq to fight for Islamic State are not representative, but the abusers and the jihadists have helped to create a new stereotype for British Pakistanis, and this time it is they who are the feared aggressors.

This, fortunately, is not the only way in which things have changed since 1971. George Khan and his children were frustrated in their ambitions. It is hard to imagine Amir Khan, Mishal Husain, Sadiq Khan, Natasha Khan (Bat for Lashes), Sajid Javid or Adil Ray having the careers they currently enjoy had they been around in the 70s. It is even harder to imagine a 70s Zayn Malik (One Direction), who is of precisely the same heritage as Khan-Din: Pakistani father, white mother from a northern town.

I recently sat down to rewatch East Is East. I thought I knew the story but seeing it again made me wonder if I had got it wrong for all those years. If one's instinctive sympathies are with George's children – as mine had always been in the past – the film appears to be about race, religion and personal identity. When I watched it recently I found my sympathies lay more with George; the man is a monster, but he is a fearful, guilt-ridden monster; a frightened man unwilling to live with the consequences of the decisions he has made, specifically the decision to marry a white woman and have children. Quite possibly I found I had more sympathies with George because of how my life had turned out: I, too, have married a white woman and we have a mixed-race daughter. When I look at my daughter, who is only three, I wonder whether she will want to know anything about the culture I was born into when she is older. She will be free to make her choices, but were she to marry a white British man and have children, they would be born British – would I just be the Pakistani ancestor they occasionally mention?

However much I sympathise with George, I emphatically do not want to become him – a man terrified that the life he knew has disappeared. That, ultimately, may be why East Is East remains such a compelling work: it explores race and belonging, but, more than that, it depicts a particular strain of masculinity that has existed across all communities and times – it is about those frightened, flawed fathers who seek to control their families because they cannot control the future.

• East Is East runs from 4 October to 3 January 2015 at Trafalgar Studios, London, SW1.