The new controversial five-in-one jab for children will be available in GP surgeries from today.

The injection replaces the separate diphtheria, tetanus, whooping cough, Hib jabs, plus the oral polio vaccine.

When it was announced earlier this summer, critics raised concerns that the new jab could \"overload\" the immune system of small children.

However, Dr David Salisbury, head of immunisations at the department of health, dismissed the claims.

\"We will actually be giving children far fewer ingredients, not more, so all the mumblings that have been going on about overloading the immune system are the wrong way round,\" he said.

\"That is even if you believe the immune system can be overloaded. This isn’t a real risk anyway.\"

The new injection is free of the mercury-based preservative thiomersal, which has been linked with autism, but the department of health stressed said this was not the reason for the change in vaccine.

Health Development Agency, UK