"Both Alex and Pedro are fine players in their own right but the time had come for them to take on a new challenge," Surrey's professional cricket manager Chris Adams told the county's website. "I wish them both the best of luck with their future plans and thank them for their contribution to Surrey County Cricket Club."
Surrey signed Collins, the former West Indies fast bowler, on a two-year Kolpak deal. Collins, 33, played 32 Tests and 30 ODIs, but as a Kolpak signing is unable to play for West Indies again without immediately becoming an overseas player.
Tudor is famed for his 99 not out for England, batting as a nightwatchman against New Zealand in the 1999 Test at Edgbaston. He began his career at The Oval and was there between 1995 and 2004 before being released after several seasons where he was more often injured than available. He moved to Essex, initially on a pay-as-you-play basis, before establishing himself as a regular in the first team, although he did not regain the form which saw him win ten Test caps as well as the 1999 Young Cricketer of the Year award. He returned to Surrey in August 2008.
Players to have signed new deals until the end of the 2011 season are the batsmen Stewart Walters, Matthew Spriegel, Arun Harinath and Michael Brown; bowlers Stuart Meaker and Simon King; and wicket keeper Gary Wilson. The seam bowler Tim Linley has signed a one-year deal.
"When I first joined Surrey I knew it would not be possible to provide immediate solutions to the club's problems," said Adams. "With this in mind, we have developed a long term structure to return to the position of the leading side in the English game. One of the key factors I have identified to help us do that is continuity. No sports team has ever benefitted from a constantly high turnover of players and I am very happy the vast majority of our squad are now able to plan for two or more solid years at Surrey.
"All the players that have recently agreed new deals have yet to reach their potential for this club and I look forward to exciting times ahead when they are all consistently performing at the height of their ability."