A couple whose 12lb baby died following a harrowing delivery at West Middlesex hospital are now celebrating the arrival of twins.

John and Sally Pattison's four-week-old twin boys, Sam and Ben, who each weighed 8lb 8oz, were born by caesarean at the Queen Charlotte Hospital in Hammersmith.

But although the couple are enjoying their happy ending, they feel they are reaching a brick wall with their continuing campaign for safer childbirth systems.

In 2004, Mrs Pattison, 32, went into labour at West Middlesex hospital, but the physical stress of the 13-hour experience almost killed her and led to the death of their baby, Amy.

The couple from St Margarets have since been trying to establish why the NHS apparently has no system for detecting and dealing with abnormally large babies.

Mr Pattison, 40, said: "The guidelines are that you should measure a woman every two weeks when she is carrying a larger than average baby. But it is left up to the individual trust to decide. There is no official protocol, only guidelines.

"The National Institute of Clinical Excellence (Nice) says it has guidelines for the management of large babies, but we are not just talking about the management, it is the guidelines for detection in the first place.

"With the management comes options, but we never had these options because the size was not identified in the first place".

A spokesman for West Middlesex hospital said: "The trust received a formal complaint from the parents. This has been fully investigated and an independent clinical report was commissioned. The report concluded that the care and treatment provided was appropriate and reasonable.

"West Middlesex does not have formal guidelines for the management of large babies and there is no expert consensus on this issue.

"However, the trust is keen to work with other hospitals to research this important issue further in the future."