A mother was given a bottle of morphine for her baby by a chemist instead of medication for a common illness.

Selina Brown was handed the super-strength painkiller – a highly addictive and dangerous drug – marked as her son’s normal prescription.

And it was only as she prepared to squirt a dose of the drug into six-month-old Riley’s mouth that she realised she had been given the wrong medicine.

Last night the pharmacy responsible apologised for the error and promised to improve its procedures to prevent the same thing happening again.

Ms Brown, 24, of Barnet Way, Hove, said her son could have died if she had not spotted the mistake.

She said: “It’s lucky I didn’t give him any, otherwise I could have been planning a funeral the next day.

“I got it in the syringe ready to give it to him. It was the morning rush.

“Luckily I realised something was different. If I hadn’t had the medication before I would have given it to him without realising. It could have been a matter of life or death.”

The bottle was tagged with her son’s name and the brand name and dosage of the medication he was taking for vomiting.

But it contained a drug called Oramorph, which is based on the same chemicals as heroin and is normally used only for people in severe pain, such as cancer patients.

Its side effects include identical withdrawal symptoms to those suffered by heroin addicts.

The mix-up happened at Ashtons Pharmacy in Dyke Road, Seven Dials, Brighton.

Riley suffers from reflux, a condition which means he cannot keep food down and was on a course of omeprazole, which was written on the label stuck to the bottle of morphine.

Oramorph is not licensed to be used on children under a year old. Where it is used for young children, the recommended dose is half what the label on Riley’s prescription instructed.

Laurence Sperey, the owner of Ashtons, said the shop had an error rate of one in five thousand when it was assessed by the NHS. He said a member of staff had been disciplined over the mistake and the firm had apologised to the family.

Mr Sperey said: “One error is too many. The medication wasn’t taken, thank God. We will learn from it and tighten up our procedures.

“All of the staff at Ashtons were badly affected by the possibility that a child could have taken something that is potentially dangerous.”

The company paid Ms Brown £200 after she complained about the wrong prescription.

Ms Brown’s grandmother, Doris Short, a former Brighton General Hospital nurse, said: “There are too many mistakes these days. Who was it prescribed for in the first place?”

A spokeswoman for the Royal Pharmaceutical Society of Great Britain said it was impossible to tell whether the oramorph would have been fatal to Riley without calculating his weight, the dosage and other factors.