A slip of paper commemorating one of the most important events in British railway history is likely to fetch more than £10,000 at auction later this month.

Experts believe the share certificate marking the Stockton and Darlington Railway is the earliest surviving example.

Little is known about how the certificate came to be preserved for so long.

Although hundreds were printed, the vast majority have been lost or destroyed, making surviving examples of huge importance to rail historians.

Certificate number 236 is dated 1823 - two years before the opening of the world's first public steam railway, using George Stephenson's Locomotion as the train.

The historic share features a vignette of a horse-drawn railroad, with a view of an industrial town, either Darlington or Stockton, in the background.

It was made out to bankers Edward Backhouse, Robert Barclay and Joseph John Gurney.

The certificate, offered for sale by a private collector at Bonhams in London on December 18, could challenge the existing record of £10,500 - realised at Phillips in March 2000 - for one issued to local solicitor Leonard Raisbeck, one of the key figures behind the ambitious project.

At a dinner held by the Tees Navigation Company on September 10, 1810, Raisbeck moved a resolution "to inquire into the practicality and advantage of a canal or a railway from Stockton and Darlington to Winston, for the more easy and expeditious carriage of coals, lead etc".

Raisbeck was a leading advocate in the heated wrangling that followed and eight years later, he proposed a similar resolution at a meeting in Darlington, which this time led to positive action.

A company prospectus was drawn up and Raisbeck was put down for ten shares, becoming joint solicitor to the prospective company, active in raising funds to enable the Act of Parliament to be obtained.

The company was incorporated in 1821 and finally opened in 1825.

By this time, 656 shares had been issued.

The original Darlington Station has been restored to its former glory and can now be viewed as part of the town's Darlington Railway Centre and Museum.