Dangers are always with us says doc.

All pen tops have a small hole in them to prevent choking should they be accidently swallowed.

But Chronicle medic and Newcastle GP Dr Mike Scott explained that sometimes this is not enough to save lives.

He said death by choking usually happens in one of two ways.

"Even if a pen top with a hole in lodges in the larynx (voice box) your body will produce mucus to protect itself and this can block the hole," he said. "It is the body's defence mechanism but it can clog up the little hole.

"The muscles around the larynx will also very quickly go into a spasm when something is swallowed, in the same way that your eyelid would automatically shut if someone was poking you in the eye.

"This could result in the airways narrowing and the brain being starved of oxygen.

"It is usually children that put things in their mouths. Fortunately most get swallowed and end up in the stomach but if they end up in the voice box, the windpipe or the airways it can be very serious.

The British Standards Institution (BSi) have specific standards regarding pen tops. In text relating to the British Standard for pen caps it says: "If a child accidentally inhales a pen top it may become lodged in the larynx and so block the trachea.

"The danger of asphyxiation can be reduced if ventilated or too large to swallow. Of course, children should be actively discouraged from sucking, chewing or otherwise putting pen caps in their mouths.

"It should, however, be recognised that despite any discouragement that they may receive, children will continue to do so...if caps are essential this British Standard minimises risk by specifying the design of ventilated caps which reduce the likelihood of inhalation and delay asphyxiation pending medical intervention."

The institution then goes on to specify the exact requirements for the British Standard pen top.

Roger Vincent, spokesman for the Royal Society for the Prevention of Accidents, said: "Obviously, this is a great tragedy, but incidents like this are extremely rare, particularly in someone of this age.

"Choking incidents tend to be among the very young children or elderly people and tend to involve food. It is a reminder again to people not to suck on pens. It is a very sad case."