Jake O'Keefe wept at a press conference at Reading police station as he appealed for Rebecca O'Keefe and Emma Douglas, 13, to get in touch.
The girls have not been seen since telling schoolfriends on Friday that they were planning an "adventure". It is thought that they are surviving on stolen food and sleeping rough on beaches.
Emma's step-sister, Melanie Juckes, 27, said: "I just want her to know that her family is very distressed and her mum is so upset she could not come today. If she can please get in touch we will not be angry." She said she thought that once the girls had announced their plans for an "adventure" they had felt obliged to go because of peer pressure. The last trace of the girls, who attend the Holt school in Wokingham, was on Saturday, when Emma withdrew some money from a bank account at a cashpoint in Brighton. Rebecca is thought to have had pounds 40 or pounds 50 on her.
Emma's father Ian Douglas, a welder aged 46, said the pair had telephoned a friend on Saturday afternoon to say they were sleeping on the beach. The pair, neither of whom had ever travelled further than the six-mile train trip from Wokingham to Reading on their own, had mentioned they wanted to visit Brighton, Newquay, Manchester and Blackpool as well as Scotland, where Rebecca's father, Derek, lives.Reuse content