Four men appeared in court today to face terrorism charges.
Zahid Iqbal, 30, Mohammed Sharfaraz Ahmed, 24, Umar Arshad, 23, and Syed Farhan Hussain, 21, are accused of discussing methods, materials and targets for an alleged attack in Britain.
This is said to have included the use of improvised explosive devices and firearms.
The men were arrested following a series of raids at their homes in Luton last week.
It is alleged that Iqbal, of Bishopscote Road, Arshad, Hussain and Ahmed downloaded computer files containing practical instruction for an attack.
The men are also said to have purchased survival equipment and collected funds for terrorist purposes.
In further charges, they are accused of possessing documents including the magazine Inspire and copies of 44 Ways to Support Jihad.
Ahmed, of Maidenhall Road, and Arshad, of Crawley Road, are also said to have held a copy of 21 Techniques of Silent Killing, while the latter is claimed to have been in possession of The Al Qaeda Manual.
Hussain, of Cornel Close, is alleged to have possessed The Book of Jihad and a copy of The Explosives Course 2.
The men spoke only to confirm their names and dates of birth at Westminster Magistrates' Court in central London.
The alleged offences are said to have taken place between last January and April this year.
District Judge Daphne Wickham remanded the men in custody, to appear at the Old Bailey on May 11.