On one side of Hyde Park Corner was a stream of pilgrims heading towards the park to see, in person, a man they very much admired - the leader of the Roman Catholic Church, Pope Benedict XVI on his first State visit to the UK.
On the other side was a very different group whose opinion of the Pope was hostile, to say the least, but whose members were determined to make their voices heard.
They had come especially to take part in a demonstration organised by campaign group Protest the Pope, which was heading from that meeting point to a rally outside Downing Street.
They all had a variety of reasons for turning up - some wishing to take a stand for secularism, others supporting feminism or gay rights and those who were primarily angry with the Vatican's stance on contraception and the way it handled sex abuse cases.
Ashley Huxley, 26, said she had only ever taken part in one protest before, but she wanted the world to know how unhappy she was with the government for part-funding the visit.
"I think it is important for us to have a democratic protest. I came by myself but I've already met so many people who agree with me.
"This man is against homosexuality - but I am a homosexual. It was important for me to come here to make this stand."
Her words were echoed by others including mother-of-one and self-proclaimed feminist Eda Anderson.
As her fellow demonstrators began chanting "No to the Pope", the teacher explained why she thought it important to bring her three-year-old daughter Isabella.
"I think it is unacceptable for the UK government to part-fund the visit of a man who does not represent me or my beliefs.
"I brought my daughter as I felt it was important for her to start learning about this.
"We need to protest and here I feel part of a group who has the same intentions as I do."
Human rights campaigner Peter Tatchell, who led the protest, said he was happy with the turnout but he had some choice words for the Pope.
"Protest the Pope is only a small organisation and we don't have any resources, especially when compared to the massive Catholic media machine," he said.
"But this shows that we represent many British people, including many Catholics."
Earlier on Saturday, during a Mass at London's Westminster Cathedral, the Pope expressed his "deep sorrow" for the "unspeakable crimes" of child abuse within the Catholic Church - his strongest apology yet.
But Mr Tatchell said this was not enough.
He said that if he had the chance to speak directly to the Pope he would ask him to hand over any secret Vatican sex abuse files and co-operate with the police.
"The Pope keeps apologising but he only apologises for the failings of others. He is not a person who deserves the honour of a state visit," he said.
Sir Ian McKellen was among the other high profile campaigning celebrities in the crowd. He wore a T-shirt which said: "Some people are gay. Get over it", a sentiment repeated on many of the banners and placards held by the protesters.
"Condoms for Africa", said one, while another simply stated, "Pope Nope".
Even segregated schools were targeted, while others chose to make their point by wearing papal robes during the demonstration.
Julian Shinns also decided the protest should be a family affair and brought his son, Frankie, 13, along.
The child protection worker said: "I have followed for some time the way the Vatican has handled the child abuse cases and I don't think they have done enough.
"I want to make my feelings clear and this is the perfect opportunity to do this."
He said his wife, a Roman Catholic, fully supported his decision to take action, while Frankie said his friends at school had been impressed by his commitment and desire to march.
Although some of the demonstrators were calling for a "secular Europe", Mr Shinns said he was happy to be a "broad Christian" and he hoped the protest would make the Vatican do more to tackle sexual abuse.
'Mistakes of a few'
It's a stance that perhaps some of the pilgrims who were heading towards Hyde Park for the evening vigil understood.
Henry Mumbi, a member of the Zambian Catholics in the UK, said he had waited a long time to see the Pope and it was an opportunity he did not want to miss out on.
The father-of-four said he hoped seeing Pope Benedict XVI would help him consolidate his faith.
He said he had no problems with the demonstrators outside the venue and added: "As a Christian you must have an open mind. People have the right to make their feelings heard.
"We have made some mistakes as a Church but the Church is made up of individuals and not everybody should be blamed because of the mistakes of a few," he said.
Fellow pilgrim Grahame Addecott, 77, from the parish of Leigh-on-Sea, in Essex said he was a fan of the Pope's conservative manner and nothing was going to spoil his enjoyment of the day.
He had even brought along a chair to sit on and make himself comfortable while the Pope spoke.
Ann Keith from St John the Evangelist in Mongeham in Kent even wore a customised jacket promoting the papal visit.
She said: "The Holy Father has come here to spread good news and so we should celebrate.
"I don't mind the protests as long as they do it over there and don't spoil our day."
Grahame Addecott's friend and fellow parishioner Francis O'Brien said: "Of course we had to come today to see the Holy Father.
"He is our Church's spiritual leader - what other reason would we need?"