A quarter of a century ago today, Sikhs all over the world watched in horror as news came in that the Indian government had invaded the Golden Temple, or Harmandir Sahib as it's traditionally known, in Amritsar, Punjab. The three-day siege of the holiest of Sikh temples, known as Operation Blue Star, was launched on a major festival. It provoked such fury that the prime minister, Indira Gandhi, was later assassinated by her own Sikh bodyguards.

It's difficult to overstate the impact that 1984 had on Sikhs and their politics, even in Britain. Gandhi's assassination was followed by systematic revenge attacks on Sikhs across India and then a brutal counter-insurgency operation that targeted Sikhs who wanted an independent homeland (Khalistan). The Indian government suspended constitutional rights in Punjab and committed gross human rights abuses against tens of thousands of people. Partly in response, an Air India flight to Canada was blown up in 1985 by Sikh militants.

Almost every year groups gather in London to commemorate these events and raise awareness of people still missing or locked up. Sometimes, the Indian flag is torched. In one report (pdf) produced for the anniversary, the whole episode it is described as the "Sikhs' Kristallnacht".

But while these facts are well documented and constantly discussed, there is less acknowledgement of how the episode has affected Sikhs since.

Firstly there is the issue of the Sikh homeland itself. The siege was an attempt to flush out separatist militants holed up in the Golden Temple. It partly resulted from pressure on Indira Gandhi to take a stronger stance against the growing separatist movement in India.

Spearheaded by the charismatic and hardline Jarnail Singh Bhindranwale, the Sikh separatist movement was accused of anti-Hindu rhetoric and importing heavy weaponry into the state. He was a controversial figure, calling for stricter codes of conduct amongst Sikhs, including calling for Sikh women to wear the looser salwar-kameez dress rather than the traditional Indian sari.

But the village preacher was popular because he was seen as the man who would almost re-create the glory days of the kingdom of Maharaja Ranjit Singh. Bhindranwale offered an easy moral alternative to other corrupt Sikh institutions and stood for Sikh self-determination.

His death not only elevated the call for a Sikh homeland, but also made him an untouchable martyr figure despite his hardline stances. Gurdwaras across the diaspora, especially in Britain and Canada, were encouraged to support separatist groups.

Although much of that separatist fervour has since dissolved, it still remains strong in parts of Birmingham and Vancouver. What isn't said enough about these institutions is that they focus much more on Indian politics than they do in supporting and looking after local communities.

The second problem is that the struggle for justice for innocent Sikhs is still far too often linked to agitation for an independent Sikh homeland. It shouldn't be. The two are separate issues and one of the big struggles in contemporary Sikh politics in Britain and Canada is that the Khalistanis (who want political power) use the human rights bandwagon to advance their own agendas. This makes it easier for the Indian government to ignore the issue.

A third problem is this: Sikhs have always felt under siege as a community since their inception – from the Mughals, the Hindu kingdoms, the Afghans, the British Raj, the carve-up of Punjab at independence, the Congress party and more recently the Hindu nationalists in India.

This sense of victimhood makes it easier for hardliners to silence dissent within the community because unity is emphasised above all. Even openly acknowledging social ills such as depression, racism (against lower caste Sikhs), domestic violence and rape is difficult.

In December 2005 the Sikh writer Gurpreet Bhatti came under sustained criticism from hardline Sikhs for writing a play about rape in the Gurdwara. There were even attempts by some Sikh groups to sue her for racism against Sikhs!

A generation on, the spectre of 1984 is fading as Sikhs look towards the future rather than the past. But the continuation of human rights abuses and the lack of justice makes it difficult. However, what Sikhs need now is a vision for the future not, one from the past. They need to revive an intellectual tradition that has stagnated for the past 25 years and think about how Sikhism can survive and fashion itself to be at home in liberal western societies.