[Update 6pm - All four suspects from 21st July now arrested]
Meanwhile it's being reported that the two men arrested today in raids in Notting Hill and North Kensington may be two of the the suspected bombers from the 21st July failed attacks. Again the BBC has the low down on this.
I've just heard on the radio that there's been a further arrest in Rome! I've just been watching Sky News. This certainly appears to have now been confirmed by several news agencies that the man arrested in Rome is Osman Hussain. He is thought to have attempted to set off a bomb at Shepherd's Bush.
The police will be making a press conference about today's dramatic events at 7pm tonight.
[Update 7.25pm - Police statement on the arrests]
I've just watched the police statement by DAC Peter Clarke. Roughly he said that it had been a day of "intense activity" and that "important developments" had been made. He confirmed that three arrests had been made in West London. One in Tavistock Square, near Notting Hill, and two men arrested at a Peabody Trust estate in Dalgarno Gardens, North Kensington. The two men there failed to surrender and "specialist tactics" were used to get the men from the building. Since then, one of the men identified himself as Muktar Said Ibrahaim. Clarke also said that "another man of interest to the investigations has been detained in Rome" and that Italian authorities named him as Hussain Osman.
No questions were allowed after the statement as nothing more could be said as it might "prejudice the right of any individual to obtain a fair trial". Clarke stressed that the safety of the public is paramount. "There will be more very visible police activity." He was grateful for the public's continuing support and understanding. However, "We must not be complacent. The threat remains, and is very real. The public must be watchful and alert. I would like to reassure the public that we are doing all we can to keep you safe". Full police press statement here.
Absolutely amazing day and it's fantastic that these guys were all alive as hopefully this will lead to even more potential bombers being arrested.
Tony had a chat with one of them after taking the picture and says in his blog "he and his armed colleagues are called out all the time, the only difference between them and the normal police force is that they aren't seen that often and hopefully that will always be the case in this country".
Jean Charles de Menezes buried in Gonzaga
Finally, we must not forget that today was also the funeral of Jean Charles de Menezes, the Brazilian man shot by police at Stockwell Tube station. This was held in his home town of Gonzaga. A London vigil at Parliament Square was also held to coincide with the funeral.