By Nic Rigby
BBC News Online
In the summer of 1940 as Germany seemed set to invade Britain, a secret army was created.
Auxiliary Units used a range of equipment
Known as the Auxiliary Units, their aim was to wreak havoc behind enemy lines as the German invasion progressed.
Their existence was a closely guarded secret.
It has only been through the work of the Museum of British Resistance Organisation in Parham, Suffolk, and through the memories of surviving former members that their work during World War II has come to light.
Now John Warwicker, who helped set up the museum, has published a history of the units entitled With Britain in Mortal Danger: Britain's Most Secret Army of WWII
In the course of his research for the book he talked to former Auxiliers across the country, including members in Suffolk, Norfolk, Essex.
The Auxilier Special Patrols consisted of small groups of men whose job was to stay behind enemy lines if the Germans invaded the UK.
The late Herman Kindred visits his underground base 55 years later.
They would hide in special underground chambers which were dotted around the country.
The plan was for them to emerge at night and attack enemy supply and ammunition dumps and sabotage enemy equipment.
The Auxiliers were the first troops to equipped with tyre-bursting mines, phosphorous hand grenades and Thompson sub machine guns imported from the United States.
John Fielding, 81, who later served in the Special Air Service in France, has strong memories of his time as a member of one of three Auxiliary Units in Norwich.
"We had very good training at Coleshill House in Highworth (Wiltshire) - training at upsetting communications, for example the use of explosives to demolish railway lines," he told BBC News Online.
John Fielding and his wife Ann at their Norwich home in 2001
"I was 18 or 19 and it was exciting. We were going to wait until such a time as the German invasion happened and then we would go into underground bases and only come out at night."
But the men were well aware of the risks they would be taking if the Germans had invaded.
"They would certainly be putting their lives in serious danger. Had they been caught they would have been shot," said Mr Warwicker.
Keith Seabrook, a patrol leader in Essex, told Mr Warwicker: "It was not a blueprint for a long life. We were completely expendable and never thought of the consequences."
As well as sabotaging German communications, Mr Warwicker discovered that Auxiliers also believed they were "authorised to shoot collaborators".
The late Herman Kindred, of the Statford St Andrew Patrol in Suffolk, admitted to Mr Warwicker that his .22 rifle with a telescopic sight could be used for "selective execution" - even of Britons if they were a danger to his operation.
John Warwicker has just published a key history
But if the Germans had invaded how successful would the secret army have been?
"Most of the Auxiliers themselves were pretty confident of their abilities," said Mr Warwicker.
"In a local area they would have been pretty effective, but there would have problems living off the land in the winter."
'Lack of communications'
They could have been hindered by a lack of a radio link up between British army and the Auxiliers.
"They had no communications. That was a serious mistake," he said.
The other question which is hard to answer is why the existence of the Auxiliers was kept secret for so long.
Mr Warwicker believes that the government refused to release the files until recently because the actions of the Auxiliers would have been illegal in the international courts.
"They would have had no justification under international law and also there could have been claims against the War Office for members injured in Auxiliary Units," he said.
With Britain in Mortal Danger: Britain's Most Secret Army of WW II edited by John Warwicker. (Published by Cerberus)