Tourism officer Gerard Traynor was returning from a Coalfield Communities Campaign conference in Swansea on regenerating former coalmining areas, accompanied by council leader Derek Thompson and councillors Alan Lockyear and Alan Napier.
Mr Thompson suffered crushed vertebrae and was taken to Ealing Hospital. Mr Lockyear suffered a fractured left leg, broken collar bone and chest injuries and was taken to Hillingdon Hospital. The condition of both men was said to be comfortable.
Mr Napier suffered a collapsed lung and was put on a ventilator. His condition is described as serious but no longer critical.
An insider said: 'It's savagely ironic, what's happened. It might make them think again.'
Mr Traynor was a very well-liked man, born and brought up in Jarrow. He was due to lead a 28-mile charity walk this weekend. He leaves a wife and three young sons.
-- Paul Claydon (50), a district auditor in London, died on 11 September. He had been a district auditor for 32 years.
-- Haringey LBC social services director Andy Ludlow suffered a fatal brain haemorrhage at his home last week and died two days before his 52nd birthday. Colleagues in Haringey say they will greatly miss him.