How should UK, US and Australia respond to Canada-India row?

<span>Photograph: Sean Kilpatrick/AP</span>
Photograph: Sean Kilpatrick/AP

Canada’s accusation on Monday that India may have been behind the car park murder of the Sikh separatist Hardeep Singh Nijjar in June – which New Delhi rejects outright – comes at an uncomfortable and unwelcome time for Britain, the US and Australia.

London, Washington and Canberra have all been prioritising closer ties with New Delhi, seeing it not just as a strategic bulwark against the fast-rising China, but also as a partner in the economic isolation of Russia after the invasion of Ukraine.

Britain is also close to striking a post-Brexit trade deal with India, possibly as soon as next month, and on Tuesday Downing Street said that negotiations would “continue as before” while Canadian investigations are ongoing.

Meanwhile, the US, Australia and Japan are partners with India in the Quad, a four-country security dialogue, that restarted in 2017.

For the moment, it is relatively easy for the western nations to adopt “a wait and watch approach”, according to Viraj Solanki, a south Asia analyst at the IISS thinktank, marking time until Canada’s investigation becomes clearer. “They will want to see how the situation develops, and engage with both countries in private,” he added.

Earlier this week, using identical language, the US and Australia each said they were “deeply concerned”. The British foreign secretary, James Cleverly, said the UK took “very seriously the things that Canada are saying” – sympathetic but non-committal statements. India, meanwhile, said Ottawa’s allegations were “absurd and motivated”.

Related: India urges its citizens to exercise ‘extreme caution’ in Canada

A complicating factor is that the close Five Eyes relationship (an intelligence alliance comprising Australia, Canada, New Zealand, the US and the UK) means that Britain, the US and Australia are likely to have a clearer picture of the evidence and intelligence Canada is relying on behind the scenes.

Whatever that is, it was strong enough for Justin Trudeau, Canada’s prime minister, to say there are “credible allegations of a potential link” to Indian government agents on Monday – although he was diplomatic enough to wait until a week after his visit to the G20 summit in Delhi before going public.

The question is what lies ahead. If it was publicly proven that the Indian state was behind the killing of Nijjar in a far-off, western country, it would be, according to Chietigj Bajpaee, a south Asia expert with the Chatham House thinktank, a gamechanger, placing India into a rather different club of countries.

“India wants to be seen as a responsible global power. It just hosted the G20 summit, and it wants to be the voice of the global south. The last thing it should want is to be associated with regimes like Saudi Arabia, accused of the killing of Jamal Khashoggi, and Russia, perpetrator of the Salisbury poisonings,” the analyst said.

Former British insiders say the UK has long been monitoring Indian intelligence activity in the UK amid accusations of the targeting of nationalist Sikhs and the spreading of anti-Pakistan disinformation. But, given wider diplomatic priorities, there has been no need to talk openly about the issue.

While China was the primary focus of the recently passed National Security Act, which updated the definition of espionage to create an offence of “assisting a foreign intelligence service”, it is understood that concerns about India were also relevant.

Tensions, though, are running high. In June, another Sikh separatist, Avtar Singh Khanda, died suddenly in a Birmingham hospital from leukaemia at the age of 35, prompting his mother, Charanjeet Kaur, to claim he was poisoned in the aftermath of Trudeau’s comments about Nijjar.

However, West Midlands police says, having conducted an investigation at the time, that the force “is satisfied that there are no suspicious circumstances” surrounding Khanda’s death. Like Nijjar, Khanda had campaigned for an independent Sikh state in India’s Punjab, Khalistan – and both were described by India as terrorists.

While Khanda’s early death appears to be tragically unfortunate, the shooting of Nijjar by two masked gunmen outside a Sikh temple in Surrey, British Columbia, is more clearcut. Canadian police will have to decide whether they are in a position to make arrests or mount a prosecution.

The worst case for western diplomats is that Canada presents unambiguous evidence in public for Indian involvement, mirroring the Saudi situation, in which relations with the west deteriorated after the murder of Khashoggi in 2018.

Bajpaee said: “In the Saudi case, a state link was essentially proven and there was bad blood in the US relationship for a while, but things have now been to some extent patched up. That would probably be the case with India. If a link to Delhi was proven in the Nijjar case, I am not sure it would undermine the Indo-Pacific pivot in the long term.”