Rail union leaders called today for an official investigation into maintenance on London Underground after days of disruption and delays caused by checks on Tube trains.
Services on the District Line were hit for the third successive day when a number of trains were withdrawn after engineers discovered brackets which seemed to be cracked during a maintenance inspection earlier this week.
London Underground (LU) said 17 trains were out of service for inspection or repair and accused the Rail Maritime and Transport union of "scaremongering".
The union announced that it was filing a report to the Office of Rail Regulation claiming that LU was "cutting corners" on Tube maintenance and calling for an investigation.
A Transport for London spokesman said: "Once again, the RMT are scaremongering. All District Line trains are being fully and properly inspected before they enter customer service. Any trains that require work are also being fully repaired before they enter service.
"We apologise to passengers for the disruption this is causing, but passenger safety is our top priority. It is also important to recognise that the issues with District Line trains were picked up through our routine maintenance programmes, and this demonstrates that our safety regime works."
LU said the District line was running with "minor delays" today, with 17 trains out of service for inspection or repair, compared with 23 yesterday.