A mutli-million-pound contract for India to purchase 27 Westland 30 helicopters was described as the British government's "Achilles heel" in relations with India following Indira Gandhi's assassination in October 1984, according to newly-declassified UK government documents.
According to the documents at National Archives, senior members of the Margaret Thatcher government feared a change in India's stance over a deal struck by the former Indian Prime Minister.
"The Prime Minister may wish to be aware that Westlands had negotiated an order of 27 Westland 30 helicopters for use in oil rig support with one of the Indian Government agencies.
"The order had Mrs Gandhi's backing and unless this backing continues at a high level it is possible that the French will intervene and the order be lost," warned Peter Warry, one of Thatcher's special advisers, in a letter issued on November 1, 1984 -- a day after Gandhi's assassination.
Further background briefing documents prepared by the UK Foreign and Commonwealth Office (FCO) alongside the British High Commission in New Delhi added: "Westlands are in the final stages of negotiating a contract for the sale of W30 helicopters (contract value 65 million pounds; 100 per cent aid financed)... India is one of the best potential sales markets with defence sales of 1.28 billion pounds since 1975."
The then British High Commissioner to India, Robert Wade-Grey, issued a warning that British Sikh celebrations in the UK following Gandhi's death could have a direct impact on the deal.
"There is even talk of a trade boycott, including cancellation of existing defence contracts," he wrote to the then foreign secretary, Geoffrey Howe, who was sufficiently rattled.
"There is obviously a wide area of vulnerability, and the Westlands helicopter contract might, in particular, offer a handy Achilles heel if the Indians were so minded," he said.
These initial exchanges led to more detailed briefs being prepared on Rajiv Gandhi, who, it was clear, would be the one to ensure the deal goes through as Acting Prime Minister.