The United Nations Security Council passed Resolution 1267 on 15th October 1999. Subsequent resolutions have also been passed - e.g. UNSCR 1333 was passed in 2000 to freeze assets of Al Qaida. Resolution 1267 was aimed at “the Afghan faction known as The Taliban.” At the time this was rather unusual in that the target of a UN Resolution was traditionally a "rogue" Member State (e.g. Iraq in the 1990s). The Taliban is certainly not a recognised “State.”
The UK passed Orders – made under the United Nations Act 1946 – with a view to giving force in the UK to Resolution 1267. The Orders were the Terrorism (United Nations Measures) Order 2006 and the Al-Qaida and Taliban (United Nations Measures) Order 2006. See HM Treasury website
Orders made under the 1946 Act are “Orders in Council” and are made by the Privy Council. After the Order is made it must be “laid before Parliament” but there is no requirement for debate or any form of approval – see 1946 Act s.1
The Terrorism Order has been quashed by the Supreme Court in HM Treasury v Ahmed  UKSC 2. Also, by a majority, the court quashed one article in the Al-Qaida Order. The judgment can be read on the court’s website.
The case is interesting in that the court has insisted that persons affected have certain basic rights which were being denied under the Orders as they stood.
It is now being reported that Britain is, along with other nations, ready to “buy off” the Taliban with “millions”. The war in Afghanistan has already been lengthy (2001) and has claimed (as at 24th January) 251 British lives. Of course, it is said that the money will go to President Karzai’s government and its use would be monitored. The Taliban would not get cash. Why then do I feel uneasy?
Addendum 31st January
Perhaps this report in The Times (Sunday 31st January) is the answer. It seems that there is a serious gulf between promises made to moderate factions by the government of President Karzai and their ability to honour those promises.
Addendum 2 - 5th February
The Supreme Court had declared the Terrorism Order and one article of the Al Qaida order to be void. That which is void has no legal effect. The Treasury asked the Supreme Court to "suspend" the operaton of its decision but the court, by a 6:1 majority decision, refused to do so. See HM Treasury v Ahmed and others No.2  UKSC 5. It appears that the government is to rush through legislation with a view to ensuring that assets which were frozen (unlawfully as it now appears) will remain frozen. The legislation will need to have retrospective effect. See The Times 5/12/10.
The question of when a court may suspend the operation of one its decisions is interesting. A suspended decision would have no effect until such time as it became operative. That is not the same thing as saying that a decision only has prospective effect (i.e. immediately effective but for the future only). The usual situation with English judicial decisions is that they have both retrospective and prospective effect.