Cough 'weakened' Queen Mother

The Queen Mother often needed a helping hand

Buckingham Palace suggested that a chest infection contracted around Christmas led to her becoming "increasingly frail".

Anyone who lives beyond 100 has already demonstrated a remarkably robust constitution.

However, men and women of this age are far more vulnerable to illnesses that others might find easy to shake off.

It was said that there was "concern" over the Queen Mother's health as long ago as 12 January, when she was struggling to overcome the respiratory infection.

The full nature of the infection has not been revealed - but elderly people are especially vulnerable to pneumonia.

This is a lung infection which can be caused by a variety of bacteria and viruses.

Attended funeral

However, only a month later she was well enough to attend the funeral service of her daughter Princess Margaret in Windsor.

Using two sticks, and with bandaged leg in 2001

However, from that point until her death, she remained at Windsor rather than travel to Sandringham or another of her homes.

In recent years, the Queen Mother has suffered a series of health problems, some of which have sparked deep concern for her health.

Prior to the chest infection, she was diagnosed with anaemia - a shortage of oxygen carrying red blood cells - in July 2001.

She was admitted to hospital and given a blood transfusion.

Fractured hips

Her hips have required two operations to insert replacement joints, the first in November 1995, the other in January 1998.

Another fall led to a fractured collarbone in November 2000, which left her in a sling for some weeks.

Her mobility had been further impaired by persistent, painful leg ulcers, which failed to heal swiftly, and required heavy bandaging.

There had been other medical emergencies, both much earlier in her life - when her appendix was removed by surgeons, who also operated to alleviate an "abdominal obstruction".

Choking emergency

There in the 1980s and 1990s, when her throat became obstructed by food on more than one occasion, firstly by a lodged fish-bone, and on two other occasions.

This was because she suffered frequent throat spasms which prevented her swallowing properly.

Another minor operation took place when her sight in one eye began to fail.

A cataract was diagnosed and removed, restoring her vision.

The Queen Mother, as well as relying on conventional medicine, reportedly had a deep interest in alternative medicines - such as homeopathy.