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LONDON, May 18 (Reuters) - Britain set out planned changes to bank ring-fencing rules on Monday that it said would create a "more agile and proportionate regime" and remove barriers to lending and investment.

The finance ministry said changes would enable banks to provide up to 80 billion pounds ($107 billion) in additional lending to businesses and would reduce duplication within ring-fenced banks, while leaving key protections unchanged.

Ring-fencing, introduced in the wake of the financial crisis, requires the largest British banks to separate their retail bank from riskier trading activities.

($1 = 0.7486 pounds)