In his Easter Sunday homily, delivered in St Mary’s Cathedral in Edinburgh, Cardinal Keith O’Brien stressed the “common ancestry” of all Christians as he paid tribute to friends in the Church of Scotland and reiterated the Catholic Church’s commitment to finding full unity.

“I propose that the reason for our increased apostolate in seeking Christian unity must be our ongoing action together in the face of aggressive secularism to maintain our Christian heritage and culture in our great country,” he said.

Pope Benedict XVI warned of aggressive secularism when during his visit to Britain last September, when he told Catholics that they must recognise the challenges that confront them on the path of Christian unity as well as in their task of proclaiming Christ today.

Cardinal O’Brien said that any Christian who had tried to live a Christian life and proclaim Jesus Christ and his teachings today “will realise exactly what the Pope meant by these words”.

“Perhaps more than ever there is that ‘aggressive secularism’, and there are those who would indeed try to destroy our Christian heritage and culture and take God from the public square. Religion must not be taken from the public square,” he said.

The Cardinal said he had been contacted recently by a Presbyterian minister in the Church of Scotland who had contrasted the British Government’s promise to act against the persecution of Christians in other countries while apparently ignoring the increasing marginalisation of Christians in the UK.

“Recently, various Christians in our society were marginalised and prevented from acting in accordance with their beliefs because they were not willing to publicly endorse a particular lifestyle,” the Cardinal said.

He pointed to the recent case against Christian guesthouse owners Peter and Hazelmary Bull who were ordered by a court to pay damages to a gay couple they refused to let stay in one of their double bedrooms.

In the face of such marginalisation, the Cardinal said Christians must work toward the full unity for which Christ prayed for.

“Even at this present time, Christians must be united in their common awareness of the enemies of the Christian faith in our country, of the power that they are at present exerting, and the need for us to be aware of that right to equality which so many others cry out for,” he said.

Whilst he encouraged Christians to have a spirit of rejoicing on Easter Sunday, he said he must also ask for another “spirit of realism” to be in their midst.

The Cardinal concluded by affirming his belief that Christianity would once again flourish in Scotland.

He said: “I say that because of my belief in the Resurrection! I say that because of my belief in the courage of those of the Christian faith today as that so many times in the past when persecution was around our forebears.

“In the face of persecution once more I say to all Christians: ‘Christians be aware of your responsibilities; it is Christ’s own image that you bear in the sacrament of baptism.

"As you aware of the past so too be aware of the strength of the faith which you, your children and your children’s children will need now and in the years which lie ahead.’”