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Bus route 423

Transport
423
Usually a Volvo Wrightbus Eclipse Gemini 3.

96% on timeof departures in the week ending 17 October 2026, leaving no more than 2.5 minutes early or 5 minutes late. Half of London's timetabled routes managed 73% or better.

The last week, day by day
Share of departures leaving on time.

Watch a day of route 423’s buses: every bus, replayed on the map. Or click a day on the chart.

The weekly figures

The share of departures that left on time.

Week endingSchool RoadHeathrow Terminal 5
21 Jun 2025no datano data
28 Jun 202594%92%
5 Jul 202593% thin93% thin
12 Jul 202596% thin93% thin
19 Jul 202594%95%
26 Jul 202591%94%
2 Aug 202595%94%
9 Aug 202598%95%
16 Aug 202596%97%
23 Aug 202597%96%
30 Aug 202598%97%
6 Sept 202591%92%
13 Sept 202597%95%
20 Sept 202599%97%
27 Sept 202598%96%
4 Oct 202595%88%
11 Oct 202598%97%
18 Oct 202598%99%
25 Oct 202593%97%
1 Nov 202599%100%
8 Nov 202597%96%
15 Nov 202593% thin98% thin
22 Nov 202596% thin96% thin
29 Nov 202597%98%
6 Dec 202593%89%
13 Dec 202598%97%
20 Dec 202595%93%
27 Dec 202597% thin96% thin
3 Jan 202696%85%
10 Jan 202698%93%
17 Jan 202697%99%
24 Jan 202698%97%
31 Jan 2026100%97%
7 Feb 2026100%98%
14 Feb 202699%95%
21 Feb 2026no datano data
28 Feb 2026no datano data
7 Mar 202699%97%
14 Mar 202699%97%
21 Mar 202697%98%
28 Mar 202698%97%
4 Apr 202696%98%
11 Apr 202695%98%
18 Apr 202698%97%
25 Apr 202698% thin95% thin
2 May 202699%94%
9 May 202698%95%
16 May 202698%96%
23 May 202694%91%
30 May 202693%93%
6 Jun 202693%94%
13 Jun 202695%93%
20 Jun 202697%98%
27 Jun 202693%95%
4 Jul 2026no datano data
11 Jul 202698%91%
18 Jul 202697%93%
25 Jul 202697%94%
1 Aug 2026no datano data
8 Aug 2026no datano data
15 Aug 2026no datano data
22 Aug 2026no datano data
29 Aug 2026no datano data
5 Sept 202698%95%
12 Sept 202693%92%
19 Sept 202699%95%
26 Sept 202697%93%
3 Oct 202698%98%
10 Oct 202699%98%
17 Oct 202698%94%

A passenger going by the timetable at Heathrow Terminal 5 would find about one departure in ten leaving more than 2.5 minutes early or 5 minutes late.

School Road
On time
98%
Cut short
1.8%
Heathrow Terminal 5
On time
94%
Cut short
0.0%

70 minutes was the longest gap between buses this week, at The Bell towards Heathrow Terminal 5, from 23:13 on Friday 16 October to 00:23 on Saturday 17 October. This excludes any gaps caused by holes in our own data. Watch it happen →

Journeys cut short

Last week: 0.9% of journeys were turned back before the end of the line in the week ending 17 October 2026. Everyone on board has to get off; for anyone waiting further along the route it's effectively a cancellation.

towards Hounslow Bus Station

Last week, 7 of 396 journeys (2%) were turned short.

  • Martindale Road2.4 km short of the end 2
  • Treaty Centre0.8 km short of the end 2
  • Bolton's Lane10.5 km short of the end 1
  • Frampton Road2.6 km short of the end 1
  • The Bell1.0 km short of the end 1

towards Heathrow Terminal 5

Last week, none of 391 journeys was turned short.

Each place is the last stop the bus was timed at before it turned round, with the typical distance it fell short of the end of the line. The five busiest are named; the rest are counted together.

Compared with TfL's own figures

QuarterTfLOurs
2025/26 Q313 Sept – 2 Jan 202687% on timeno figure
2026/27 Q11 Apr – 26 Jun 202690% on timeno figure

TfL's figures come from its own tracking equipment and its own timetable; mine are computed from the buses' public position feed. They are the same calculation on independent data, so they should broadly agree and move together rather than match exactly.

About this data
Data collected, week ending 17 October 2026
100% of the week. This is the share of the week for which we hold bus location data at all, across the whole of London rather than for this route. A week under 60% is not published; under 90% it is marked as thin.
Departures observed
  • School Road: 214 departures seen
  • Heathrow Terminal 5: 219 departures seen
A guide to how much evidence sits behind this week's figures, not a measure of the service.
How it is measured
Every day, 05:00–23:59. On time means leaving no more than 2.5 minutes early or 5 minutes late. A day with less than four hours of data collected shows no daily figure. How these figures are made.
Gaps in the record for this period (39)

Most recent first. Hover a week on the chart and it will name the gap behind it. Most are a few missing hours on an otherwise ordinary day.

  • 17 Sept 2026 partial day, no data 12:00-12:59: our collector was down (machine off or power cut)
  • 28 Aug 2026 partial day, no data 20:00-23:59: our collector was down (machine off or power cut)
  • 29 Jul – 26 Aug 2026 no collection: the volunteer BODS archive was down and our own collector had not yet started
  • 28 Jul 2026 partial day, no data 11:00-23:59: no collection: the volunteer BODS archive was down and our own collector had not yet started
  • 7 Jul 2026 partial day, no data 15:00-15:59: gap in the volunteer BODS archive (its collector was down)
  • 5 Jul 2026 partial day, no data 06:00-11:59: gap in the volunteer BODS archive (its collector was down)
  • 4 Jul 2026 partial day, no data 06:00-21:59: gap in the volunteer BODS archive (its collector was down)
  • 2 Jul – 3 Jul 2026 gap in the volunteer BODS archive (its collector was down)
  • 8 Jun 2026 partial day, no data 07:00-08:59: gap in the volunteer BODS archive (its collector was down)
  • 7 Jun 2026 partial day, no data 12:00-12:59, 18:00-19:59: gap in the volunteer BODS archive (its collector was down)
  • 6 Jun 2026 partial day, no data 12:00-12:59, 16:00-16:59, 18:00-18:59: gap in the volunteer BODS archive (its collector was down)
  • 27 Apr 2026 partial day, no data 12:00-12:59: gap in the volunteer BODS archive (its collector was down)
  • 21 Apr 2026 partial day, no data 06:00-11:59: gap in the volunteer BODS archive (its collector was down)
  • 20 Apr 2026 partial day, no data 15:00-23:59: gap in the volunteer BODS archive (its collector was down)
  • 16 Apr 2026 partial day, no data 12:00-15:59: gap in the volunteer BODS archive (its collector was down)
  • 28 Feb 2026 partial day, no data 06:00-18:59: gap in the volunteer BODS archive (its collector was down)
  • 16 Feb – 27 Feb 2026 gap in the volunteer BODS archive (its collector was down)
  • 15 Feb 2026 partial day, no data 16:00-23:59: gap in the volunteer BODS archive (its collector was down)
  • 30 Jan 2026 partial day, no data 20:00-23:59: gap in the volunteer BODS archive (its collector was down)
  • 25 Dec 2025 no bus service on Christmas Day
  • 23 Dec 2025 partial day, no data 06:00-07:59: gap in the volunteer BODS archive (its collector was down)
  • 5 Dec 2025 partial day, no data 06:00-08:59: gap in the volunteer BODS archive (its collector was down)
  • 24 Nov 2025 partial day, no data 17:00-17:59: gap in the volunteer BODS archive (its collector was down)
  • 17 Nov 2025 partial day, no data 06:00-09:59: gap in the volunteer BODS archive (its collector was down)
  • 15 Nov – 16 Nov 2025 no London vehicles in the national feed — TfL's export to BODS was down (the volunteer archive itself was collecting)
  • 14 Nov 2025 partial day, no data 06:00-07:59, 13:00-23:59: gap in the volunteer BODS archive (its collector was down)
  • 31 Oct 2025 partial day, no data 06:00-07:59: gap in the volunteer BODS archive (its collector was down)
  • 17 Oct 2025 partial day, no data 06:00-07:59: gap in the volunteer BODS archive (its collector was down)
  • 10 Oct 2025 partial day, no data 06:00-08:59: gap in the volunteer BODS archive (its collector was down)
  • 3 Oct 2025 partial day, no data 06:00-11:59: gap in the volunteer BODS archive (its collector was down)
  • 19 Sept 2025 partial day, no data 06:00-08:59: gap in the volunteer BODS archive (its collector was down)
  • 5 Sept 2025 partial day, no data 06:00-09:59: gap in the volunteer BODS archive (its collector was down)
  • 1 Aug 2025 partial day, no data 06:00-09:59: gap in the volunteer BODS archive (its collector was down)
  • 18 Jul 2025 partial day, no data 06:00-09:59: gap in the volunteer BODS archive (its collector was down)
  • 8 Jul 2025 partial day, no data 06:00-08:59: gap in the volunteer BODS archive (its collector was down)
  • 6 Jul – 7 Jul 2025 gap in the volunteer BODS archive (its collector was down)
  • 5 Jul 2025 partial day, no data 18:00-23:59: gap in the volunteer BODS archive (its collector was down)
  • 4 Jul 2025 partial day, no data 06:00-14:59: gap in the volunteer BODS archive (its collector was down)
  • 25 Jun 2025 partial day, no data 06:00-11:59: gap in the volunteer BODS archive (its collector was down)

For latest timetable and route information, see TfL's official page.

Contains public sector information licensed under the Open Government Licence v3.0; bus data via the DfT Bus Open Data Service and Transport for London. Figures are computed from observed bus positions, every day, 05:00–23:59. How these figures are made. Bus positions from the Department for Transport’s Bus Open Data Service (BODS); the Department for Transport cannot warrant the accuracy or quality of the data published there. Positions before September 2026 come from the Bus Open Data archive generously built and kept by Open Innovations, with thanks. Route lines and stops: Powered by TfL Open Data. Contains OS data © Crown copyright and database rights 2016. Geomni UK Map data © and database rights [2019]. These pages and the bus replay are built independently from open data: Transport for London, the Department for Transport and the bus operators had no part in making them, and none of them endorses them. Not for planning a journey.