Colin Graves has identified a "watershed moment" as English cricket calls on key stakeholders to give the go-ahead for a new city-based Twenty20 tournament.

The England and Wales Cricket Board chairman took the much-anticipated step on Tuesday to trigger a postal ballot of all 18 first-class counties, the Minor Counties Cricket Association, MCC and 21 recreational boards to officially endorse the constitutional change required for the eight-team competition to begin in 2020.

For those plans to continue, as seems almost inevitable, a minimum 31 of the 41 organisations consulted must respond positively over the next 28 days to the suggested amendment in the ECB's Articles of Association which will allow - on a one-off basis - the inauguration of a competition involving only eight teams, rather than all 18 counties.

After the executive board agreed to dispatch the literature during a Lord's meeting, Graves welcomed the unanimous decision.

"The ECB board today (Tuesday) gave their unanimous support to trigger a formal process to change the game's Articles of Association and allow a new T20 competition," he said.

"Our members have seen the evidence for why the new T20 proposal is the right way to reach new audiences, create new fans and fuel the future of the game.

"Together, we can now take a huge opportunity to not only create a deeper engagement with those who currently follow cricket but to attract a whole new audience and ensure the sustainability of our game.

"This is a watershed moment for us all to make the whole game stronger."

Kent and Sussex were among the three counties still to be convinced last September when a 16-3 show-of-hands nonetheless gave the ECB its initial mandate to press ahead with the eight-team format to the exclusion of other options.

As both prepared for their own annual general meetings on Tuesday night, at which respective chairmen George Kennedy and Jim May were set to step aside after a long tenure each, indications were that the ECB could expect broad approval over the next month.

The format will be similar to the Big Bash in Australia or the IPL (Getty)

Kennedy said: "I think the most important thing we wanted to make sure of was that the financial arrangements were appropriate.

"The £1.3million (annual share of revenue to each county) for four years is enhanced by a percentage of the revenue post year four ... so financially it looks okay.