By Claire Heald
BBC News in Whitehall
The family of Jean Charles de Menezes have taken their call for a public inquiry into his death in London directly to Number 10 Downing Street.
Alessandro Pereira hand delivered his letter to No 10
A month after the Brazilian was shot by police at Stockwell Tube station, his cousin Alessandro Pereira called for the officers to be brought to justice.
He handed in a letter at No 10 and was clapped by up to 200 protesters, with some chanting "No justice; No peace."
They then marched to Metropolitan Police headquarters at Scotland Yard.
Mr Menezes died on 22 July, after police officers wrongly linked him to the attempted Tube bombings a day earlier.
Outside Downing Street, Mr Pereira said that since the shooting "more and more lies" had come out and he wanted "truth and justice" for his cousin, who was 27.
He read from a statement that said: "I have just handed a letter to the British Prime Minister Tony Blair on behalf of the family both here and in Brazil.
"I am calling on him to make sure that those responsible for the murder of Jean are brought to justice.
"The family also calls for a full public inquiry into all the circumstances into the death - including the shoot-to-kill policy and the lies we have been told by the Metropolitan Police.
"Every day we discover more and more lies. We have heard too many, we simply demand truth and justice."
In the crowd, British and Brazilian protesters said they wanted to show solidarity with the Menezes family and backed their demands for a further inquiry.
The Independent Police Complaints Commission is already looking into the circumstances surrounding the shooting.
Some protesters back a public inquiry
Londoner Bergis Daver, 64, said he had felt compelled to join the protest when he saw newspaper headlines about CCTV footage from Stockwell Tube station going missing.
"The family should be treated with a bit more respect," he said.
"(Metropolitan Police Commissioner) Ian Blair has been extremely pompous, cold and uncaring. They're a poor family, they're not English speaking. The family needs support."
He said there should be some kind of full inquiry: "I think it's very difficult to find out what's happened, but the sooner the better, or it will be lost from public consciousness."
Katie Russell, a 28-year-old artist, said she was horrified by the idea of someone being shot on the Tube.
"I am a pacifist, so I'm against the shoot-to-kill policy and it sounds just monstrous what happened to this man.
Shamiul Joarder feels people are now more anxious
"It's important British people come out as well so the authorities know they're upset and shocked by it. The more people, the more likely the police will review the shoot-to-kill policy.
"I feel the police aren't taking responsibility and there has to be a full public inquiry."
Stop and search
Shamiul Joarder, 24 and a London civil servant, said the Tube shooting and increased stop and searches were making people feel more nervous not secure.
"A lot of my friends have been stopped, it seems that we're being victimised," he said.
Rafael Lanz: Thinking of a return to Brazil
"When a non-white person goes on the Tube now, you don't know what the police are capable of."
Rafael Lanz, 32, a Brazilian IT consultant from Cambridge, said the shooting had strengthened his thoughts on leaving the UK - a move first considered after the start of the Iraq war.
"I don't want to live in a country where the government is simply unaccountable," he said. "I would like a real public inquiry."
Demonstrators gathered on Whitehall for about one hour before marching through Parliament Square to take their protest to Scotland Yard.
In a statement on Monday, the Met said it had briefed Mr Menezes' cousins in the UK two days after the shooting.
Officers told them that he had not run into the Tube station, had not been wearing a padded jacket and that he had not vaulted the ticket barrier - as had been reported at the time - a spokesperson said.
Sir Ian Blair has previously rejected claims of an attempt to cover up events surrounding the shooting and said some of the disputed statements had never been provided by his force.