The failings in the support system provided to asylum seekers may have contributed to the death of a 10-month-old boy.

Terry Bamford, chair of the Westminster Local Safeguarding Children's Board, an independent body involved in child safety, wrote a letter highlighting his concerns about the transitional period between receiving National Asylum Support Service (NASS) and benefits from the Department of Work & Pensions (DWP) after the child died.

A serious case review into the death of Child EG found his mother, who had sought asylum from Africa in 2005, was seriously ill and "socially isolated". The review found EG's death was accidental.

The baby's mother, Mrs G, was suffering from a rare brain infection linked to HIV, which left her unconscious long periods, meaning she was unable to feed the child.

Mrs G had moved to Westminster from Birmingham in 2009 following allegations of domestic abuse. On 8 March, 2010, she called an ambulance to say the child was having breathing difficulties but when the crew arrived, it was discovered "the baby had been dead for some time".

A post-mortem examination showed that there was no food in the baby's stomach or digestive tract. Mrs G was arrested for child neglect but was admitted to hospital almost immediately, where she died two days later from her medical condition. A second child was taken into care.

The case review concluded: "The tragedies of EG's death and that of his mother provided an opportunity for addressing organisational weaknesses or individual failings identified in the course of the review.

"Crucially, no single or series of actions or decisions that might reasonably have been expected of professionals could have predicted Mrs G's sudden illness and therefore initiated any responses to prevent EG's death."

Questions have now been raised over the current support system for asylum seekers, as the family appears to have fallen through the cracks during the transitional period between leaving the NASS and entering mainstream council care.

The case review states: "Westminster Local Safeguarding Children Board should write to the National Asylum Support Service and Department for Work & Pensions to express its concern about the adverse consequences on vulnerable children and the resulting additional pressure on local professional agencies which are triggered in the transitional period between withdrawal of support by the National Asylum Support Agency and entitlement to Benefits."

In his letter, Bamford says the review shows that the withdrawal of NASS support resulted in the family becoming destitute, with social care and health agencies having to provide hand-outs to "tide them over".

He wrote: "Safeguarding vulnerable children is a priority for public services. Joined up government should be able to manage the transition from one form of public support to another without households having to face the additional stress of uncertainty and insecurity."

"I would be grateful if your agency could review the position and steps be taken to remedy this situation."

James Thomas, director of family services at Westminster City Council, said: "This was clearly a tragic case involving a family with complex health needs. We share the Westminster Safeguarding Children Board's concerns about the current transitional support available to successful asylum seekers before they are linked up to mainstream support services.

"We would be happy to work with central government to improve transitional support arrangements in order to better protect vulnerable children and families."

A UK Border Agency spokesperson added: "This was a tragic incident and we extend our sympathies to the family. The welfare of asylum seekers and children is a key concern and we have already made several improvements to transitional arrangements.

"Organisations housing asylum seekers for UKBA while claims are being considered must now notify local authorities when an application is successful, and refugees can remain in asylum accommodation for one month after the decision. In addition we give funding to voluntary groups to provide support and advice to refugees."

Westminster is home for many of the world's wealthiest people living in hisotric distrcts including Belgravia and Mayfair. The average house price in the the borough is £1 million.