The children have not been missing before and although they have packed clothes and taken money we are very concerned about them, particularly in this cold weather. It is believed they have left on their own accord.
We are continuing to carry out a number of enquiries to try and locate Sophie and Jack and are being supported by a significant number of force resources.
We are now appealing to the public to help us with this search - if you have seen either of the children today or have any information about where they may be, please contact us immediately.
More top news
Police have arrested four men in connection to the suspected terror-linked murder of a police worker in Sydney.
Volkswagen could start recalling cars containing emissions cheating software in January, according to the firm's new chief executive.
A toddler survived for days on his own after his mother collapsed and died as she fed his one-year-old brother - who also choked to death.