The contestants finally discover they are not alone - this is a race, and only member of the team that reaches the island first is in with a shot at the £200,000 prize. With both groups way behind schedule, will this new information spur them on? Meanwhile, moles David and Alex return to dish the dirt, and two members of each team face a dilemma - do they take 10 anchors back to the build or secretly pocket £10,000?

As the two sides begin to make good progress, host AJ Odudu presents them with a curveball - any team member can put themselves forward to switch beaches. At least one person from each group must move to their rivals, and if no one volunteers, then it's up to the team leaders who goes.