Four radical Islamists have today admitted an al-Qaida-inspired plot to detonate a bomb at the London Stock Exchange.
The Muslim fundamentalists' group wanted to send five mail bombs to various targets during the run up to Christmas 2010 and discussed launching a "Mumbai-style" atrocity.
A hand-written target list found at one of the defendant's homes listed the names and addresses of London Mayor Boris Johnson, two rabbis, the American Embassy and the Stock Exchange.
The total of nine men admitted various terror crimes at Woolwich Crown Court and will be sentenced next week.
"Lynchpin" Mohammed Chowdhury (aged 21) and his London accomplice Shah Rahman, (aged 28) were followed by undercover detectives on November 28, 2010, observing Big Ben, Westminster Abbey, the London Eye and the Palace of Westminster.
The conspiracy involved nine defendants - the London duo, three from Cardiff and four from Stoke - but was stopped by undercover anti-terror police before firm dates could be set for attacks.
The terrorists met because of their membership of various hardcore Islamic groups and stayed in touch over the internet, through mobile phones and at specially arranged meetings - held in parks in a bid to make surveillance difficult.
The nine, all British nationals, were due to stand trial at Woolwich Crown Court but changed their pleas.
Chowdhury, of Stanliff House, Tower Hamlets and Shah Rahman (aged 28) of St Bernard's Road, Newham, both London, admitted preparing for acts of terrorism by planning to plant an improvised explosive device (IED) in the toilets of the London Stock Exchange.
They admitted the crime after a Goodyear hearing was held to give them an indication of their maximum sentences.
The judge, Mr Justice Wilkie told Chowdhury he would receive 18-and-a-half years and Rahman, 17 years.
But the duo will only serve in the region of six years - because five are served on licence, prisoners only serve half their term as standard and they have already been behind bars for more than 12 months.
Brothers Gurukanth Desai (aged 30) of Albert Street, and Abdul Miah (aged 25), of Ninian Park Road, both Cardiff, also admitted the same count.
The quartet aimed to plant the bomb "with the obvious attendant risk but without any intention to cause death or even injury but with the intention to terrorise, damage property and to cause economic damage", said Christopher Blaxland QC, Chowdhury's barrister.
Three of the Stoke defendants admitted a lesser, specific charge - engaging in conduct for the preparation of terrorism between November 1 and December 21, 2010 - namely travelling to and attending operational meetings, fundraising for terrorist training, preparing to travel abroad and assisting others in travelling abroad.
Usman Khan (aged 20), of Persia Walk, Mohammed Shahjahan (aged 27) of Burmarsh Walk and Nazam Hussain (aged 26) of Grove Street, all Stoke, admitted attending those operational meetings in Roath Park, Cardiff on November 7 and in a Newport country park on December 12.
Omar Latif, (aged 28) of Neville Street, Cardiff, admitted attending the meetings with the intention of assisting others to prepare or commit acts of terrorism.
The fourth Stoke defendant, Mohibur Rahman, admitted possessing an article for a terrorist purpose on December 20 2010.
Rahman (aged 27) of North Road, admitted being in possession of two editions of the al Qaida magazine, Inspire, for terrorist purposes.
The nine were not members of al-Qaida but were inspired by the terror network and its former Yemeni boss, American-born Anwar al Awlaki, who was killed last year in a drone strike after leading al Qaida in the Arabian Peninsula (AQAP).
The nine defendants "were implementing the published strategy of AQAP", said Andrew Edis QC, for the prosecution.
AQAP use internet propaganda to inspire radicals to carry out attacks against the nations in which they live.
Though no firm dates were set and no homemade bombs created, the defendants had the wherewithal to do it. it was alleged.
They possessed the al Qaida magazine Inspire, which contained a feature: "Make A Bomb In The Kitchen Of Your Mom."
The threats were not just facing London.
The Stoke quartet talked about leaving homemade bombs in the toilets of their city's pubs and discussed travelling abroad for terror training.
Chowdhury and Rahman had Bangladeshi backgrounds like their Welsh accomplices, whereas the Stoke terrorists had Pakistani backgrounds.
They also discussed how to make a pipe bomb.
A jury had been sworn in to hear the trial before the men changed their pleas to guilty.
Addressing the jurors as they were discharged today, Mr Edis said that the four involved in the London Stock Exchange plot had not intended to maim and kill.
He said: "Their intention was to cause terror and economic harm and disruption. But their chosen method meant there was a risk people would be maimed or killed."
Referring to Khan, Shahjahan and Hussain, he said the group had planned for at least one of them to travel to a terrorism training camp in Kashmir along with other British nationals.
"It was clear that acts of terrorism would be committed on that's person's return," Mr Edis said.
Mohibur Rahman had owned copies of Inspire magazine, published by al-Qaida in the Arab Peninsula, which included bomb-making recipes, he added.