Domestic one-day cricket in England will revert to 50 overs per side from the 2014 season, the England and Wales Cricket Board have announced.
Following a review conducted by former International Cricket Council president David Morgan, it was decided the national team will benefit from replicating the international standard 50-over format.
The ECB confirmed the change while announcing a revised structure of the domestic game between 2014 and 2017, which will also see the first 14 County Championship matches starting on a Sunday.
There is no change to the current two division structure, but the Friends Life t20 will be expanded from 10 to 14 group-stage games for each county.
Most will be played on Friday evenings, with the top eight counties advancing to the quarter-finals, with the winners going on to an unchanged Finals Day.
The renamed Clydesdale Bank 50 will feature a reduction in group stages games from 12 to eight, with eight teams progressing to the knockout stages.
An ECB release statement read: "There was no compelling preference from spectators for 40-over cricket rather than 50-over cricket, and therefore the format from 2014 will replicate the 50-over format played by the national team.
"Consistent with feedback from the players, there was a strong desire to retain the LV= County Championship in two divisions of nine teams."
ECB chief executive David Collier added: "The research study conducted by Populus was the largest piece of market research ever conducted on county cricket.
"The board agreed with the views of spectators and players in retaining a 16-match LV= County Championship which has proven very successful since its introduction in 2000."