5.80.0.0/15

ip:	5.80.0.0 host5-80-0-0.range5-80.btcentralplus.com
loc:	United Kingdom, Gloucester (England)  
isp:	AS2856 British Telecommunications Limited » BT Public Internet Service »  131.632 ms
route:	5.80.0.0/15, UK-BT-20120613 - British Telecommunications PLC, GB (London (South Bank)) ... 
reg:	5.80.0.0/15, GB, RIPE, 2012-06-13
asn:	AS2856 - BT-UK-AS British Telecommunications PLC, GB
addr:	  PP1 Floor1 Orion Adastral Park Martlesham Heath IP5 3RE Ipswich UNITED KINGDOM
online:	  3.849 » latency: 50 ms (74ms) 

see also:
   5.81.0.0/16      AS2856   BT-INFRA BT Infrastructure Layer, GB