The Share Aware campaign, with its slogan, 'Get Your Share of Great British Companies', is the first of its kind ever to be launched in the UK.

The advertising blitz is being backed by major companies such as British Airways, BT and Tesco.

The new slogan will be seen in newspapers and on posters at 200 main-line stations.

Fewer private investors since trading went electronic

The Exchange wants people to see shares as a long term investment which have outperformed most other forms of savings over the last ten years and can be used as a way of providing for retirement.

The Exchange said: "There is a growing need for all of us to make greater provision for the future, and the stock market can play an important part in that."

Millions of people became shareholders for the first time last year after a wave of building societies chose to join the stock market. Even so the number of private shareholders has fallen over the last few years.

The Exchange controversially introduced rules several years ago that effectively blocked private investors from buying shares in the majority of new issues until the stock started trading.