If it is 0151-548-3XXX (or +44-151-548-3XXX) then it's a BT landline in Knowsley, Merseyside.
http://www.ofcom.org.uk/telecoms/ioi...istered/#geog1
In my experience, some PBXs are configured to include the +44 (UK) code on the front of their caller ID so your phone may be displaying that.