Value of heavily indebted company has plummeted more than 90% since it bought chain of 1,400 bookmakers

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Evoke, the London-listed gambling company that owns William Hill and the 888 online casino brand, has said it is considering a sale or breakup of the group, after warning of a £135m hit from tax increases announced in last month’s budget.

In a statement to the stock market, the heavily indebted company said it had appointed bankers at Morgan Stanley and Rothschild to explore potential options to secure its future.