Two aspects of the service are singled out for praise. The report says the anaesthetists and the haematology department, which provided blood for the patients, responded well under difficult circumstances.

Of the women who died, six were Asian, two African, one Afro-Caribbean and one European. The hospital serves half a million people in Brent and Harrow, two boroughs with large black and minority ethnic populations.

The causes of death varied. Strokes following pre-eclampsia (very high blood pressure) were the cause in three cases, with bleeding after giving birth in four other cases. One women died of viral encephalitis, one of a cardiac arrest.

The hospital investigated the deaths from a predominantly legal point of view, as if seeking to defend itself, the report says. Common factors were not found, but the commission says that they did exist and should have been identified.

Marcia Fry, the commission’s head of operational development, said: “We hope this report gives some answers to the families involved.

“We expect trusts across the country to read this report. Most women give birth safely. But there are risks and the NHS must ensure it does all it can to reduce them. There can be no excuse for failing to learn the lessons from tragedies of this kind.”

Since April 2005 three additional consultants and 20 more midwives have been recruited. The inspectorate also believes there is a better team working among consultants, obstetric staff and midwives.