A passport which was forged by tragic British heroine Edith Cavell to enable a French soldier to escape German-occupied Belgium during the First World War has come to light 103 years later.

The courageous nurse signed the fake German passport to allow Louis Mossini to flee into neutral Netherlands.

She saved the lives of 200 Allied soldiers before she was arrested for treason, found guilty and executed by the Germans on October 12, 1915.

Nurse Edit Cavell was executed by German authorities in October 1915 on suspicion of espionage after she was betrayed by two men who exposed her role in helping allied soldiers escape occupied Belgium into neutral Holland with the use of forged passports

Miss Cavell forged this passport for French soldier Louis Mossini, who was one of 200 allied troops who managed to escape captivity before the 49-year-old nurse was betrayed

The execution of Miss Cavell caused a major international incident including criticism from the United States who were still two years away from joining the conflict in Europe

Her death aged 49 at the hands of a firing squad sparked international condemnation.

It was also used by British authorities to boost recruitment into the armed services as her image was printed on posters encouraging young men to join up.

According to her 86-page file which was held at the National Archives, some in the military wanted to use Miss Cavell's death as justification for executing German female spies caught in Britain who had previously been sentenced to prison.

Now the passport which enabled Louis Mossini to escape will be sold tomorrow by auctioneers Henry Aldridge & Son, of Devizes, Wiltshire, and is tipped to sell for £700.

A special coin was struck featuring Miss Cavell and Belgian nurse Marie Depage, who died when the RMS Luisitania was sank off the coast of Cork by a German submarine on May 17, 1915

Also included in the auction is a memorial coin commemorating Cavell's life and several contemporary postcards documenting her execution.

The items have been consigned from the David Gainsborough Roberts collection, a large collection compiled by the late Jersey-based collector who died last year.

Auctioneer Andrew Aldridge said: 'This passport was forged by Edith Cavell on behalf of a French soldier.

'It is a very, very rare object in her hand and an incredible piece of history.

'She helped a couple of hundred soldiers escape from German-occupied areas before she was arrested, accused of treason, found guilty and shot.

'There was a great international outcry and international condemnation at the act of horrific barbarity.

'She was a heroine.'

The memorial coin carries the faces of Cavell and Belgian nurse Marie Depage, who was killed in the sinking of the Lusitania on May 7, 1915.

The postcards depict the shocking moment Cavell, in her nurse's uniform and prostrate on the floor, is shot by a German officer, an act described as a 'cowardly murder'.

The sale also features a programme for a memorial service held in Cavell's honour at St Paul's Cathedral in London on October 29, 1915.

Cavell was born in Swardeston, near Norwich, in 1865.

The Imperial War Museum has this photograph which shows the stone which marks the spot where Miss Cavell was executed at the Champ de Tir in Brussels

Ms Cavell's execution was used by authorities to encourage recruitment

An archive of memorabilia related to Ms Cavell will be sold by auction tomorrow in Wiltshire

Among the archive is this card printed for a memorial service at St Paul's Cathedral

Following the war, authorities in Belgium erected a memorial in Brussels to Miss Cavell

After living and working in Belgium as a governess, she returned to Britain to look after her unwell father.

This experience inspired her to become a nurse and in 1896 she enrolled at the Royal London Hospital in Whitechapel, completing her training two years later.

Cavell held a number of roles in British hospitals before being invited back to Brussels where she became the matron of the first nursing school in Belgium.

During the war, she cared for all the wounded, including German and Austrian soldiers who were fighting against the British.

The night before her execution, she said: 'Patriotism is not enough. I must have no hatred or bitterness towards anyone.'

The sale takes place tomorrow.