Alistair Darling was considering increasing VAT to 18.5% to help pay Britain's debt, another data handling bungle has revealed.
A draft version of a document containing details of discussions about increasing the VAT rate in 2011 was published on a government website by mistake.
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The VAT information should have been removed before the final version of the document appeared on the Office of Public Sector Information website.
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Shadow chancellor George Osborne said the document showed Gordon Brown had a "secret plan" to increase VAT permanently after the next election, according to the Metro newspaper.
The revelation comes just a day after chancellor Alistair Darling announced a 13-month reduction in VAT from 17.5% to 15% starting next Monday.
A treasury spokesman said last night that the change to 18.5% was just an option that was considered and later discarded.