By Daniel Sandford
BBC home affairs correspondent
In foot-high letters and in black and red, the words "a new beginning for the mosque" were printed on a banner draped from the second-floor window.
Abu Hamza al-Masri was banned from preaching inside the mosque
The incoming trustees of Finsbury Park mosque could not have made their intentions more clear.
There was a heavy police presence as over 200 Muslim men, many of them dressed in suits, attended Friday prayers - the first under the new regime at the mosque.
The khutbah, or sermon, took as its theme how Muslims need to connect better with the rest of humanity.
The new trustees, co-ordinated by the Muslim Association of Britain, had seized the mosque last Saturday, reclaiming it for the mainstream Muslim community in north London.
The Board of Trustees has always been the legal owner of the Central North London Mosque, informally known as Finsbury Park Mosque.
But their power was eroded by the controversial cleric Abu Hamza al-Masri. One senior member of the Muslim Association of Britain said it had been "hijacked by Hamza's mob".
Mr Abu Hamza turned the mosque into the public face of the extremist jihadi movement in Britain.
The former Guantanamo detainee Feroz Abassi has written about his time there. He describes how he was encouraged to go to Afghanistan to attend a training camp.
Richard Reid, the failed shoebomber, also passed through the mosque, as did Djamel Beghal, who is currently on trial in France for plotting to bomb the US embassy in Paris.
Now the extremists have been cleared out of the offices and the rooms where they slept.
Dr Azzam Tamimi, of the Muslim Association of Britain, says the plan is to outnumber the extremists to persuade them to stay away.
"For the first few Fridays we will be organising for our members from across London to come and pray here so that we have a strong majority. We will not tolerate anyone who will seek to abuse the mosque," he said.
Worshippers continued to pray outside the mosque during 2004
The mosque cost £8m to build and will be able to take more than 2,000 people for prayer once the women's section has been re-opened.
The trustees now want to turn it into one of the most important centres for the Muslim community in London.
But there was an edgy feel to Friday prayers. No-one knew what to expect. The police officers in the area easily outnumbered the number of Muslim men attending the mosque, as a police helicopter flew overhead.
But apart from a couple of young hotheads, one of them hiding his face with a scarf, there was no trouble.
Finsbury Park Mosque has made a fresh start.