Jack Straw has ruled out changes to the UN Charter to allow pre-emptive military action such as that launched against Iraq.

Giving evidence to the foreign affairs select committee on Tuesday, the foreign secretary argued that the "understanding" of existing international law would have to change to reflect the "new realities" following the September 11 terrorist attacks in the United States.

"There is not the remotest chance of securing an amendment to the UN Charter," he said.

"There is a need for jurisprudence in the international community, where it is appropriate to take military action, to develop to take account of the new realities."

He described the military action in Kosovo in 1999, aimed at preventing the ethnic cleansing of Albanians by the Serbs, as a "major advance" in this area.

His comments follow those by the prime minister in Sedgefield earlier this month, when he argued that such a move could be needed "to prevent [a] threat materialising".

But Straw argued that "having thought about this a great deal", ministers concluded that this would not be possible.

Iraq

Giving evidence, the foreign secretary argued that European countries were at risk from terrorist attacks, regardless of whether or not they supported the Iraq war.

He highlighted the case of President Johannes Rau of Germany, who cancelled a visit to the east African state of Djibouti following warnings of a specific threat from terrorists linked to al Qaeda.

"Every country in Europe understands that it has no immunity from terrorism, regardless of the stand which they took on Iraq," he said.

Straw also confirmed that the UK would not be involved in a special tribunal for the trying of Saddam Hussein, currently being established by the Iraqi Governing Council, if the death penalty remains as an option.

"A lot of consideration has been given to how far we could participate in the establishment of a tribunal and its operation if it has capital punishment as its supreme penalty," he said.

"We have ruled out explicitly any British government involvement in the role of the prosecutor if capital punishment is available."