Thompson departs for Tranmere.
The 23-year-old will now join Tranmere Rovers on a permanent basis, having spent the last couple of months on loan with the Wirral club.
The centre half joined the U's initially on loan from Portsmouth under the management of Joe Dunne in November 2012, before his move was converted to a permanent one in the January transfer window.
His time at the U's was affected by injuries and he went on to make 22 league appearances plus one in the cup in just over two years at the Weston Homes Community Stadium.
He of course also scored one of the crucial goals away at Bury in the 2012/13 season, helping the U's to a crucial three points in their quest for survival in League One.
Josh has now signed a deal to take him to the end of the season with Tranmere and we wish him all the best for the future.