David Carter is the father of Josh Carter & Nathan Carter. Liz Carter broke up with David when Nathan was 12 as he forgot Nathan's birthday. Josh never got to see him and in Series 4, He were desperate to find out about him so he found out that he had gave his watch to Nathan and Nathan put it in his time capsule. So josh dug it up so he could find the watch but he got caught by the police.
After being bailed out with an warning, Nathan makes Josh realise he doesn't need to find out about his dad as he has better family members that will look out for him.