The compensation limit for people who lose money if their bank, building society or credit union goes bust, has increased from £50,000 to £85,000.
The new limit starts on Friday and applies to every customer at each authorised firm.
The new limit is part of a Europe-wide requirement for each country to offer compensation equivalent to 100,000 euros.
Compensation will be paid by the Financial Services Compensation Scheme.
The Financial Services Authority (FSA) said the new higher limit would cover the "vast majority" of UK savers.