Where should Christians fit in when it comes to the public sphere and national debates? It is a question many have struggled with, and in the present time it has never seemed more pertinent.

In the age of social media, where these kinds of discussions are played out in front of a larger audience than ever, there are more avenues to share the Gospel, just as there are more chances to drive people from the Church with badly represented Christianity.

In a lecture at Heythrop Philosophy and Theology College in London, the oldest of the Catholic Jesuit schools, Lord Daniel Brennan QC dived into the question of the Christian's responsibility in modern public life.

Lord Brennan, an experianced barrister and president of the Catholic Union of Great Britain, said Christians were living in "the era of I", obsessed with what he called "the cult of the individual".

"Our job as Christians, is to ensure that the era of I does not turn into an eon."

He continued: "We don't talk about 'we' any more. Only 'I'. Unless we want something, then we say 'we have rights', and 'we' is just a tool for 'I'.

"I hear people talk about 'the absolute rights of the individual'. Individuals have rights, yes, but absolute rights? That's absurd."

Although he acknowledged that there were of course many people in today's society who were acting selflessly, Lord Brennan said he was speaking of the dominant culture as expressed in our media.

Lord Brennan shared Pope Francis's vision on this point: "In the prevailing culture, priority is given to the outward, the immediate, the visible, the quick, the superficial and the provisional."

He described newspaper columnist Melanie Phillips as someone he "almost always disagreed with" but admitted he could not help but find her use of the phrase "the post-moral society" as an accurate summary of the spirit of the age.

"Today, the question is not so much what is right, but what suits," he said.

Lord Brennan said Christians needed to become better communicators of the message, and take cues from how the non-believing world receives information.

"This isn't a 19^th century debating hall anymore," Lord Brennan said, referring to the power of the internet. As a case in point, he spoke of a female Ukrainian student whose video call for help received 4 million hits in less than 12 hours.

"The challenge is how we communicate well while preserving the clarity of thought," Lord Brennan continued.

Although he cautioned that Christians needed to avoid being consumed by the "bafflegab" often present on the internet, he was positive about the power of the one-liner in capturing people's attention.

"Dialogue can be started and ended with a one liner," Lord Brennan suggested.

"Pope Francis is a master of this. He is not a polysyllabic writer."

He did not deny that such an undertaking would be easy, and quoted Winston Churchill on this point, who famously said: "It takes me hours to prepare my short speeches."

But he claimed it was absolutely necessary and not only that but that it was far preferable to engaging in the kind of "self-gratifying acts of Christian chest beating" that he claimed are sometimes seen coming from the church.

He argued that no one will come to Jesus by being told what to think and suggested instead "a sense of humour, especially in communicating our theology".

"Why are we always so po-faced about our religion?

"A Christian should have a smile on his face. We're not here to bore the pants of people! We're here to show them the true joy of what it is to be a Christian."

Issues close to his own heart include opposition to euthanasia and modern slavery.

Sharing a story about better communicating these issues, Lord Brennan spoke of a meeting he had with a group of Scottish anti-euthanasia campaigners.

"I met with them and they asked me what the anti-euthanasia group in England was called. I told them we called it Care not Killing, and they told me 'well what kind of name is that! What does that tell people?' so I asked them 'Well what do you call it up here', and do you know what they said? 'Don't Kill Your Granny'."

He spoke with concern on the quality of life for disabled people, quoting Baroness Jane Campbell of Surbiton, a disabled Peer suffering from spinal muscular atrophy, who said of the upcoming assisted dying bill: "Once you pass this kind of law, people like me will be regarded as expendable."

Although he acknowledged that to many people this may seem like an extreme scenario, he noted how George Orwell said: "It is amazing how the intellectual mind can make itself believe anything."

Speaking about modern slavery, Lord Brennan said: "This is a truly international problem. We have to be at the forefront of fighting it."

Although he acknowledged that the task for Christians in this regard was exceptionally difficult, he called upon them to be a "creative minority" in Britain today.

Speaking of the Gospel, Lord Brennan said: "We've got the treasure, why don't we spend it in the right way?"

He looked at the challenge presented to many British and European Christians by Pope Francis. In response to a question about the radicalness of the new Pope, Lord Brennan said: "I don't think he is radical. It is just that we in Europe think he's radical because we are so spiritually fatigued."

Taking inspiration from the pontiff in his summing up, Lord Brennan again quoted him saying: "Challenges exist to be overcome. Let's be realists without losing our joy, our boldness and our hope filled commitment."