Pakistan's The News claims that the ECB have stuck a clause into the tour Memorandum of Understanding (MoU) that allows the team to petition a change of venue while in the middle of the tour itself.
"The ECB has informed the PCB that the association representing the English players has expressed certain reservations citing security and safety concerns over playing in Pakistan," the source was quoted as saying.
"Some of the players have apparently told their board to have an understanding with the Pakistan Board that would allow them to refuse to play at any venue if they have any concerns about playing there."
The clause would allow England team to pull out of a game at the 11th hour citing security concerns, a move that would cause immense inconvenience to the organizers and the TV broadcasters, and most importantly, the paying public.
The clause was inserted after Richard Bevan, the players' association representative, and John Carr, ECB director of operations separately met PCB officials in Pakistan.