Omar is walking through the park and meets his brother Ahmed playing football in the rain. Ahmed's umbrella goes from small to big for a close-up, then back to small again.
Omar's water pistol was placed on his laptop but then appears behind the laptop and other objects on the table without anyone touching it.
When Barry is driving the group to the airport in his Citroen Xantia, he pulls over in a huff and swallows the key to stop them going. However, the key he produces and swallows is a Ford key, not a Citroen key.
Additionally, the car is fitted as standard with a keypad immobiliser, requiring a security number to start - so Omar's attempt to hotwire the car would not have succeeded in real life.
The extremist instructor has a belt of ammunition over his shoulder. These are fake as they have no primers.
When Omar and Waj are running from the drone strike a member of camera crew can be seen in the background (top right of the screen).
The "lions" travel to London to detonate their devices at the London Marathon. However, the streets clearly show signs for Sheffield traders - including many 0114 (Sheffield) telephone numbers. Additionally, the double decker buses are the wrong color.
Omar is seen travelling on a Supertram heading towards Halfway on the blue line. However, he gets off at Meadowhall, which is not on this line.