An urgent investigation has been launched after a school handed the wrong six-year-old girl to a grandfather – and he did not notice.

The pensioner went to Gillingham's Napier Primary School on Tuesday morning to pick up his granddaughter for a doctor's appointment.

But instead of taking his granddaughter out of class, staff brought a different girl in the same year with the same first name.

Undeterred, the man, in his 70s, took the confused six-year-old on a bus to the Gillingham Medical Centre a mile away.

She was prescribed liquid paracetamol, so he picked up the medicine inside the centre and dropped her back at school in Napier Road.

The girl's father, who asked for her to stay anonymous, said the story unravelled when his daughter came home and said "here's my medicine".

The shocked family read the details on the bottle and realised it had the wrong surname.

He said: "My daughter's been known to tell a tale or two so I took her to the surgery and the doctor said 'I saw her this morning with her grandfather'."

"I went ballistic. I was boiling inside. The first thing I thought was the worst. I had to ask my daughter the sort of questions no parent ever wants to ask, 'did he do this, did he do that'.

"When your daughter has been walked round town and taken on a bus by a strange man it makes you sick to the stomach. It's every parent's worst nightmare.

"My daughter's quite a shy girl and she's not very outspoken and she got confused."

The father added: "Everyone knows to tell their children not to go with strangers, but I want to tell every parent in that school – tell them again tonight.

"If it had been some sort of repeat prescription or injection it would have been administered to my daughter.

"The practice manager of the surgery said she's been there for 22 years and she's never seen anything like it.

"Thank God it was an innocent thing done by a confused old gentleman."

The girl's only living grandfather said: "I couldn't believe it. The first thing I thought was Maddie McCann.

"Why are they sending someone who can't even recognise his own granddaughter to pick her up?"

The family have contacted their MP as well as Kent Police and head teacher Zerina Slade called all staff in for a crisis meeting.

She said: "The safety and care of all of our children is of the utmost importance to us and we are treating this matter extremely seriously.

"As soon as we realised this had occurred, we launched an investigation. This has not only involved speaking to staff to find out how this could have happened, it has also involved reviewing all our procedures in connection with children's safety.

"I have also spoken with the mother of this child to offer our sincere apologies over this regrettable incident and to assure her that we are reviewing all our safeguarding policies – with the help of the council – to ensure this never happens again."

Gillingham and Rainham MP Rehman Chishti said: "I am very concerned about this and will be asking the school to fully investigate.

"The safety of all children under the school's care is paramount and they should urgently review all procedures."

A Kent Police spokesman said: "We have spoken to both families involved and the school. Technically no criminal offence had taken place, so it has been passed to social services.

"If it later came to light that a crime had been committed it would be referred back to us."

Stories you might have missed

Homes struck by lightning and roads flooded

Perverting justice charge over sex assault claims

Coach erupts into fireball on motorway

Video: Farm staff spooked by ghostly objects