Established in 1907 by Army reformer R B Haldane, the TA was at the time Britain's response to the continental concept of "a nation in arms".

Originally known as the Territorial Force, people across the country were asked to give up their time to help in "homeland defence".

And they did - in their thousands.

Dozens of regiments were formed and in 1921, such was the gravitas placed on the volunteers that they changed their name from a Force to an Army.

So, the Territorial Army was born.

Strength

Over the years successive governments have increased and decreased numbers depending on policy, politics and war commitments, but the force has remained and is still a strong one today.

There are currently more than 40,000 members of the TA, making up a quarter of the total strength of the British Army.

One regular Army officer who works with TA units said the old "Dad's Army" image of the volunteers was a thing of the past.

He told BBC News Online: "Most people join up for the challenge. We get people from a complete range of professions, everything from vicars to people earning serious money in the City.

"The TA is a very important part of the Army and I think it's seen as that these days."

Sign-up

Britain is one of a very few countries to retain a permanent volunteer army.

British TA soldiers have played a vital role in the war in the Balkans and the Gulf and are currently deployed in many of the more than 80 countries their regular counterparts are in.

To sign up to the TA, volunteers:

• must be a citizen of the UK, Commonwealth or Republic of Ireland,

• must be aged between 17 and 32

• must be prepared to get fit and take a medical (there is no pre-standard of fitness required)

• do not need to have any academic qualifications.

When attending training, officers earn from �30.27 to �130.33 a day while soldiers collect between �27.29 and �64.69.

The minimum period of service is three years and the number of days required each year to serve are 27 for members of most units, 19 for specialist units.

The 1998 Strategic Defence Review made it a requirement that TA volunteers are liable to be called out to operate alongside regular forces though both the volunteer and their employer may seek exemption.