A man charged with trying to blow up a transatlantic plane had been on a UK watch-list, the government has said.

一名试图爆炸一架美国飞机的男子已经进入英国严密监视名单。

Umar Farouk Abdulmutallab was refused a visa

Umar Farouk Abdulmutallab, 23, was refused a visa in May and placed on a security list after he applied¹ to study at a bogus伪造的，假的 college.

He targeted a Detroit-bound flight from Amsterdam阿姆斯特丹 with explosives hidden in his clothes, it is claimed.

Police are searching several London properties linked to the Nigerian ex-University College London student.

Father's fears

Home Secretary Alan Johnson said people on the same list as Mr Abdulmutallab could not come into the UK, although they could pass through the country in transit在途中 and were not permanently永久地 banned.

Those on a more serious watch-list for terror-related reasons would automatically have their details passed on internationally, but this is not always the case with information about a person rejected because of concerns about an academic application.

Mr Abdulmutallab had also been on the US's lowest risk watch-list since November, although it allowed him to travel on planes flying into the country.

He was placed on it by US authorities after his father contacted both Nigerian and foreign officials to express his concerns after his son had ceased中止，中断 contact with his family.

The home secretary told BBC Radio 4's Today programme the US authorities should theoretically have been informed that Mr Abdulmutallab was on a UK watch-list, and he doubted there had been a "hiccup⁴打嗝" in procedures.

He said the UK's border security was extremely "robust粗野的，强健的": "We have a very, very strong border in this country, we have strong security measures. We've now monitored 135 million people trying to enter the country."

Mr Johnson also said there was a need to establish the nature of Mr Abdulmutallab's activities while he studied in the UK from 2005 to 2008.

He said he did not believe that Mr Abdulmutallab had been acting⁵ alone, adding that police and security services were examining whether he had been radicalised激进 while at University College London (UCL).

UCL has confirmed that a person of the same name and description as Mr Abdulmutallab took an engineering with business finance degree at the university between September 2005 and June 2008, when he successfully graduated.

In a statement on Monday, UCL said it was "deeply shocked" by recent events.

"During his time on the course, Mr Abdulmutallab never gave his tutors any cause for concern and was a well mannered, quietly spoken, polite and able young man," it said.

A spokesman also confirmed that Mr Abdulmutallab was president of UCL's Islamic society between 2006 and 2007.