The British police has revealed the names of the three persons that carried out the London terrorist attack on 3 June 2017. They were Youssef Zaghba, Khuram Shazad Butt and Rachid Redouane (see photo).
Youssef Zaghba was a dual citizen of Italy and Morocco. He had been placed under surveillance in Italy ever since he was arrested at Marconi airport, Bologna, taking a one-way flight to Istanbul . Upon being arrested, he had declared to the police officers: “I am leaving to become a terrorist” . His mobile phone contained videos of jihadists  and the Italian Intelligence services had warned their British colleagues that he was dangerous when he left for the UK. However the MI5 did not consider him to be dangerous.
Khuram Shazad Butt was a dual citizen of Pakistan and the UK. He appeared last year in the Channel 4 documentary, The Jihadis Next Door. He is a member of the Wahhabist al-Muhajiroun, which in September 2006, had organized, shooting and combat training at the Jameah Islamiyah School (East Sussex). Its leader, Anjem Choudary, linked to Hizb-ut-Tahrir, had not been sentenced at that time; but today he is serving a five and a half year prison sentence for defending Daesh. Khuram Shazad Butt was fighting on the side of The Shariah Project (a tentacle of the al-Muhajiroun), to convince bars and grocery stores owned by Muslims, to desist from selling alcohol.
The British Minister for Home Affairs had banned the al-Muhajiroun organization, then in 2010 it banned three other organizations which tried to resurrect it (one of which is Islam4UK), and another three in 2014 (including The Shariah Project). While the British Intelligence Services’ surveillance of the national activities of the al-Muhajiroun caused them some alarm, these same services had encouraged some of their actions abroad, notably in Afghanistan, India (Kashmir) and Russia (Caucasia).
Rachid Redouane would appear to be a national of both Morocco and Libya.
Furthermore, according to the New York Times, Salman Abdi, author of the Manchester terrorist attack on 22 May 2017, is likely to have established contacts with al-Battar al-Libi, a brigade of Daesh when he was in Sabratha, Libya  .