Wicketkeeper-batsman John Simpson will be Finn’s vice-captain throughout the competition.

Malan’s involvement in England’s Test team will rule him out of the entirety of the competition’s group stage, which takes place across a three-week period coinciding with England’s preparation for and playing of their two-match series against Pakistan.

Middlesex director of cricket Angus Fraser said: “Steven is at the stage in his career where he is very keen to take on greater responsibility and, with the expected absence of Dawid Malan with England, he is highly likely to get the opportunity to guide the club through most of our Royal London One-Day Cup group games.

[caption id=”attachment_58900″ align=”alignnone” width=”800″] Dawid Malan has made himself a mainstay of England’s Test side[/caption]

“John is in a similar position to Steven and the pair will have the brain and experience of Eoin Morgan to help guide them.

“These opportunities are great for the development of both players and I look forward to watching them at work.”

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Finn said: “I am delighted to have been asked to captain the side in Dawid’s absence.

“Having played at Middlesex since the age of 15 I am extremely proud to have been given this opportunity and we can hopefully move the side forward in white-ball cricket and achieve success in this year’s competition.”