UK-Channel Islands-8: 0.23× baseline latency
What we measured
| Cable | UK-Channel Islands-8 |
| Segment | Goonhilly Downs, GB → St. Ouens Bay, JE |
| Detected | 2026-05-20 15:01 UTC |
| Resolved | 2026-05-20 16:30 UTC |
| Duration | 1h 29m |
| Observed latency | 9.9 ms |
| Baseline | 42.9 ms · 0.23× |
| Increase | +123% |
| Severity | warning |
Who is affected
Countries where UK-Channel Islands-8 comes ashore, how much of their submarine diversity this cable represents, and what our measurements into them show.
| Country | Dependence on this cable | Other submarine cables | What the measurements show |
|---|---|---|---|
| Jersey resilience index: 42 · vulnerable |
1 of 3 cables (33% of submarine diversity) | Guernsey-Jersey-4, INGRID | average 11 ms over the last day vs 27 ms over 30 days - faster |
| United Kingdom resilience index: 97 · resilient |
1 of 67 cables (1% of submarine diversity) | 2Africa, Amitie, Apollo +63 more | median 82 ms today vs 69 ms over 30 days (102 routes) - slower |
Dependence is structural (share of the country's submarine cables), not a traffic share: real traffic distribution across cables is not public.
Path analysis
Traffic kept the same route. Latency rose without a visible path change, which points at congestion or a fault on the existing route rather than a reroute.
Cross-probe verdict. Only one probe saw it. We treat this as a probable false positive and label it as such.
Timeline
- Alert 2026052001: warning - ratio 2.23x
- Alert #124 improving: 1/3 consecutive OK
- Alert #124 resolved: RTT 9.92ms (baseline 42.87ms), 3 consecutive OK
Detection method
Latency is sampled continuously from our probe network. An alert opens when round-trip time to a monitored endpoint holds above its rolling baseline, and closes automatically once it returns. Full method is described on the methodology page.