The Bank of England has named a Birmingham man suspected of being involved in an alleged plot to blow up passenger planes in mid-air.
Acting under the instruction of Chancellor Gordon Brown and on the advice of police and the security services, the bank froze the assets of Tayib Rauf, 22, and 18 other suspects who were among the 24 people arrested on Thursday.
In a statement on its website, the Bank of England said it had directed that none of the frozen funds "should be made available, directly or indirectly to any person, except under the authority of a licence".
The UK remains on a "critical" level of alert against terrorism and air passengers at UK airports are expected to face widespread disruption again following the introduction of new anti-terrorism measures including a ban on hand luggage.
The plot, which was described as an attempt to commit "mass murder on an unimaginable scale" by blowing up passenger jet, may have been thwarted just days before it was due to be carried out.
The terrorists' plan was to detonate liquid-based based explosive devices smuggled in hand luggage on aircraft leaving UK airports for the US.
If successful, the plot - which US officials said bore some of the hallmarks of al Qaida - would have been a terrorist "spectacular" on a par with the 9/11 atrocity.
Police had searched a business property in the Alum Rock area of Birmingham on Thursday afternoon. Uniformed officers were on guard outside the two-storey shuttered building in Belchers Lane while colleagues carried out a detailed examination of the scene.
West Midlands Police refused to confirm whether its presence at the address was connected with the anti-terror operation or whether any arrests had been made there.
Speaking at the scene, local councillor Ansar Ali Khan said: "I was informed that the police had raided this place and there was the possibility of arrests. I was really shocked at this news. This ward is a multi-racial, multi-ethnic area and people live in peace and harmony. It is a diverse ward and we have never had a problem. This is a difficult time for the area and for the country and I urge all communities in this area to stand united."