The four, aged between 23 and 26, were to appear in court on Tuesday to be formally charged, a police spokesman said.

"The charges against them relate to allegedly obtaining and possessing money to fund terrorism or possessing articles or material which provide instruction or training to make firearms or explosives," the spokesman said.

"The offences are alleged to have taken place on or before December 2."

He said two of those charged were residents of Dudley, a suburb of the central city of Birmingham, while the other two were living in Luton, just north of London. No names were released.

The men were arrested in pre-dawn raids across England on 2 December.

Raids

British police have launched a series of such raids in the past two weeks that have led to the arrest of about 20 people. The country is on a heightened state of alert against attacks in the run-up to Christmas.

Sajid Badat, a 24-year-old British Muslim, was arrested on 27 November at his home in Gloucester in southwest England. He was charged on Thursday with conspiring to stage a bomb attack with "shoe bomber" Richard Reid, the Briton jailed in the United States for trying to blow up a passenger plane.

Richard Reid is now in a US jail

Badat, who is reported to have recently finished studies at an Islamic centre in northwest England, is to be brought before the Old Bailey criminal court in London on 11 December.

Another suspect, Noureddinne Mouleff, 36-year-old unemployed Algerian national, was charged on 3 December with "being in possession of items or articles connected to the commission, preparation or instigation of terrorism".

He was also charged with conspiring to defraud banks. He is to appear before a London court on Wednesday.

Britain has been on a high security alert since the weekend before US President George Bush's state visit to London on 18-21 November and the 20 November bombing of the British consulate and HSBC bank in Istanbul.