都說過境倫敦需要過境簽證，我迷糊了，哪位有類似經曆的請幫忙

持中國護照，美國簽證，經倫敦去美國，朋友們的答複都是需要英國過境簽證，但是英國外交部網頁上寫的不需要簽證啊，是我理解錯了，還是新政策，下麵是該網頁的內容：Direct Airside Transit Visa (DATV) nationals - 18 November 2003

In addition to needing a visa to enter the United Kingdom nationals of the countries listed below, unless exempt, also require a visa to transit through the UK, known as Direct Airside Transit (DATV). Read our Visitors guidance for more information.

Afghanistan Liberia
Albania Macedonia
Algeria Moldova
Angola Nepal
Bangladesh Nigeria
Belarus Palestinian Authority
Burma Pakistan
Burundi Rwanda
Cameroon Senegal
China, Peoples Republic of Serbia and Montenegro
Colombia (including documents issued by
Congo, Democratic Republic the United Nations Mission
of in Kosovo)
Ecuador Sierra Leone
Eritrea Sudan
Ethiopia Somalia
Gambia Sri Lanka
Ghana Turkey
India 'Turkish Republic of Northern Cyprus'
Iran Uganda
Iraq Vietnam
Ivory Coast Zimbabwe
Lebanon

Certain exemptions to this requirement have been introduced and apply to all DATV nationals. The following categories of traveller are not required to hold a DATV and may still benefit from the Transit Without Visa (TWOV) concession:

holders of valid US/Canadian visas who also hold a ticket to or from the US/Canada routed via the UK. This will include a period of 48 hours after the expiry of the US/Canadian visa for those leaving the US or Canada to allow for those who choose to leave at the very end of the validity of their visa;

行期臨近，多謝幫忙