He said the Arab state - where alleged underpants bomber Umar Abdulmutallab linked up with al-Qaeda - was both "an incubator and potential haven" for terrorism.

 

The PM said several terror cells were known to be trying to target Britain and other countries.

 

In response, a new "no fly" list will ban suspects worldwide from boarding flights headed here.

 

And there will be a larger list of people who will face enhanced security checks before geting on a plane to Britain.

 

Mr Brown revealed that national carrier Yemenia Airways had agreed to suspend the flights "with immediate effect".

 

The moves follow the alleged bid by former London student Abdulmutallab to blow up a jet over Detroit, US.