Could this be a Merlin?

I first saw this bird on a railing in front of us last Sunday and he/she is now loitering at the top of the building, a good vantage point for the field opposite. It has yellow legs, which may not be apparent from the attached photos. It looks to me like a juvenile though I am no expert, and seems too light in colour for a Peregrine Falcon. Could it be a Merlin? I have a sound recording on my phone but not sure if I can upload it here.