rewiring flat roof extension

I need to add a wire for a light and socket in a utility and need to go to the consumer unit that it less than 2 metres away. Can I channel the wall along the ceiling and reach the consumer unit horizontally? Going through the ceiling under the flat roof could be messy and don't fancy taking part of the ceiling off.

 

That's great help, thanks. The light circuit for the utility was feeding from the extension and needs a separate cable.

 

I decided to go through the ceiling for a circuit ring and light circuit. Will connect tomorrow. Thanks for advice and diagram!