England are in advanced talks with Ireland about playing a four-day test at Lord's next July, before the Ashes series. It would be England's first test against Ireland and their first four-day test since 1971.
The test is viewed by England as an essential part of their preparation for the Ashes. The 2019 series is expected to begin only 11 days after the World Cup final at Lord's.
For those who play both formats, it is likely to be their only first-class game in the five months before the Ashes. The probable dates of the test would be July 18-21.
The England and Wales Cricket Board is keen to trial four-day tests, with chairman Colin Graves and chief executive Tom Harrison publicly supporting plans to explore the concept.
For home boards, four-day tests are cheaper - virtually all tests, even in England, lose money on the fifth day.
Boards and broadcasters believe that, by being played from Thursday to Sunday - like golf tournaments - tests would be easier for fans to watch. They would also take up less time in the sport's overcrowded schedule.
While four-day tests are likely to become more common, the International Cricket Council has confirmed that all matches in the new World Test Championship - which launches with the Ashes series next summer - will be played over five days.
For the foreseeable future, four-day tests are likely to take place only if the match involves Afghanistan, Ireland or Zimbabwe, the three test nations not included in the nine-team championship.
Ireland will view the proposed fixture as a seminal moment in their cricketing history. They were granted test status last year - the match against Pakistan last month was their inaugural test, and they impressed in losing by five wickets.
The ICC approved four-day tests last year. Revised playing conditions include 98 overs per day - rather than 90 in five-day tests. They also allow the follow-on to be enforced if a side have a first-innings lead of 150 runs, rather than 200 in the five-day form.