UK-Channel Islands-8 cable: latency up to 3.8× normal, 23 Aug 2026
What we measured
| Cable | UK-Channel Islands-8 |
| Segment | Goonhilly Downs, GB → St. Ouens Bay, JE |
| Detected | 2026-08-23 22:31 UTC |
| Resolved | 2026-08-24 00:32 UTC |
| Duration | 2h 0m |
| Observed latency | 7.1 ms |
| Baseline | 39.7 ms · 3.79× |
| Increase | +279% |
| 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 28 ms over 30 days - faster |
| United Kingdom resilience index: 100 · resilient |
1 of 68 cables (1% of submarine diversity) | 2Africa, Amitie, Apollo +64 more | median 103 ms today vs 74 ms over 30 days (1011 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. Other measurements did not confirm the event. We treat this as a probable false positive and label it as such.
Timeline
- Alert 2026082301: warning - ratio 3.79x
- Alert #176 improving: 1/3 consecutive OK
- Alert #176 improving: 2/3 consecutive OK
- Alert #176 resolved: RTT 7.1ms (baseline 39.73ms), 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.