LONDON, Aug 17 (Reuters) - London"s FTSE 100 index will lose its second largest company by market capitalisation if shareholders back plans by global resource giant BHP Group (BHP.AX), (BHPB.L) to end its dual listing structure and make Australia its primary stock market. BHP has previously come under pressure from some shareholders, notably activist investor Elliott Advisors, to simplify its structure, but had said any gains would be less than the cost of change. Now the discount of London-listed stocks is at its deepest in more than three decades, BHP, which on Tuesday reported its best annual profit in nearly a decade, said it planned to get rid of its London listing. read more Shareholders are expected to vote on the unification at meetings in the first half of 2022. If the plan gets board and shareholder approval, the London Stock Exchange will lose a major player. BHP has 128 billion pounds ($176.22 billion) in market cap, second only to AstraZeneca (AZN.L) with around 131 billion pounds, Refinitiv data shows. BHP is the biggest company by market capitalisation on the Australian stock exchange (.AXJO). The value of British stocks versus global peers has been depressed by the combined impact of Britain"s departure from the European Union, a weak pound and a lack of tech stocks, which have been the big beneficiaries of the disruption caused by the pandemic. read more London-listed shares (.FTSE) are trading at 12.6 times forward earnings, that compares to 17.3 times for the Australian benchmark. Following news of the plan to end the London listing, BHP"s London shares rose 6% by 1352 GMT, outperforming the wider market. Jamie Maddock, equity research analyst at Quilter Cheviot, said BHP"s departure is bad news for UK-focused investors as country index trackers would be forced to sell their shares. The move would also reduce significantly London"s exposure to the mining sector. David Madden, market analyst at Equiti Capital in London said the London stock market would still be attractive and noted it has attracted a surge of initial public offerings this year. "The London Stock Exchange’s deep liquidity pool will ensure it remains popular for listings", he said. Last year, consumer brands company Unilever (ULVR.L), which like BHP had a dual-listing, merged its Dutch and British corporate entities and Unilever NV"s Amsterdam-listed shares ceased trading. ($1 = 0.7264 pounds)