The State of the Internet report by Akamai records that Oxford is 5th in the world for broadband speeds, clocking in at 14.4 Mbps. Their report looks at average measured connection speeds of cities where at least 50,000 unique IP addresses are recorded. Oxford faired well in the UK coming 5th, whilst other UK cities included within the top 100 were Southampton (57th, 8.4 Mbps), Bristol (58th, 8.3 Mbps) and Cambridge (73rd, 7.8 Mbps). The Top 3 results were all in the United States and were 18.7 Mbps, Berkeley, CA; 17.5 Mbps, Chapel Hill, NC; and 17.0 Mbps, Stamford, CA.
The average for the United Kingdom was 3.7 Mbps, only slightly pipped by the United States at 3.8 Mbps. Thankfully we were well above the global average of 1.7, but we did fall far behind South Korea at the top with 11.7 Mbps, Hong Kong, 8.6 Mbps and Japan, 7.6 Mbps.
It's unclear why Oxford holds such a clear speed advantage over other UK cities. It is an area that has been enabled for BT's 21C network so broadband line speeds could be higher perhaps due to this, or take up of higher speed services from Virgin Media could be more predominant here. Oxford is also close to the 'M4 corridor,' popular with high-tech companies so could see an increase in speed due to the people who live in the area craving faster broadband.