[cisco-voip] Looking for a VoIP Service Provider in U.K

[Muqeemuddin Syed]

Hi All,
We have a Cisco IP Telephony enviroment at my company. We want to use
a VoIP service provider for all our international calls.
Since majority of our calls are bound for U.K or European
desitnations, I prefer the service provider to be based from U.K so
that the call charges can be comparitively less to U.K and Europe.
Can somebody inform if they are aware of any such provider. 
We have call managers and Cisco 3745, 3725 routers. We do not want to
lease any international links to U.K initially. If we notice the
quality of calls is bad, we would certainly consider the option of
leasing a frame-relay link to U.K as well.
Thank You