Cardinal Keith O'Brien, the Roman Catholic Archbishop of St Andrews and Edinburgh, will use his Easter Sunday Homily to launch an attack on the Government's Human Fertilisation and Embryology Bill.
Here is an extended extract from his sermon:
At this time, as well as thinking of the death and resurrection of Jesus Christ we are asked to consider again what I have described as the 'essential aspect of a Christian vocation - namely to be a missionary people'.
I think that there is a greater need than ever before for each and every Christian to be aware of that call at this present time.
So many people are worried about the future - the possibility of banks failing; the increased cost of living with regard to food, petrol and many of those things which we find essential; our concerns about climate change and global warming; our increasing worries about the dangers of nuclear disaster.
But I think that a fundamental concern of all of our people at this present time, and one which we ourselves as Christians must take very seriously, is that concerning the future of human life itself.
The beliefs which we have previously held, and the standards by which we have lived throughout our lives and by which Christians have lived for the past 2,000 years, are being challenged at this present time in ways in which they have never been challenged before!
The norm has always been that children have been born as the result of the love of man and woman in the unity of a marriage.
That belief has, of course, long been challenged.
However I believe that a greater challenge than that even faces us - the possibility now facing our country is that animal-human embryos be produced with the excuse that perhaps certain diseases might find a cure from these resulting embryos.
What I am speaking of is the process whereby scientists create an embryo containing a mixture of animal and human genetic material.
If I were preaching this homily in France, Germany, Italy, Canada or Australia I would be commending the government for rightly banning such grotesque procedures.
However here in Great Britain I am forced to condemn our government for not only permitting but encouraging such hideous practices.
Our Prime Minister, Gordon Brown, has given the government's support to the Human Fertilisation and Embryology Bill.
It is difficult to imagine a single piece of legislation which, more comprehensively, attacks the sanctity and dignity of human life than this particular bill.
With full might of government endorsement, Gordon Brown is promoting a bill that will allow the creation of animal-human hybrid embryos.
This bill represents a monstrous attack on human rights, human dignity and human life
He is promoting a bill which will add to the 2.2 million human embryos already destroyed or experimented upon.
He is promoting a bill allowing scientists to create babies whose sole purpose will be to provide, without consent of anyone, parts of their organs or tissues.
He is promoting a bill which will sanction the raiding of dead people's tissue to manufacture yet more embryos for experimentation.
He is promoting a bill which denies that a child has a biological father, allows tampering with birth certificates, removing biological parents, and inserting someone altogether different.
And this bill will indeed be used to further extend the abortion laws.
Further it seems that Labour MPs are not to be allowed a free vote on this bill and consequently are denied the right to vote according to their conscience - a right which all other political parties have allowed.
This bill represents a monstrous attack on human rights, human dignity and human life.
In some other European countries one could be jailed for doing what we intend to make legal.
I can say that the government has no mandate for these changes: they were not in any election manifesto, nor do they enjoy widespread public support.
The opposite has indeed taken place - the time allowed for debate in parliament and indeed in the country at large has been shockingly short.
One might say that in our country we are about to have a public government endorsement of experiments of Frankenstein proportion - without many people really being aware of what is going on.
Many excuses are being made for this present legislation, particularly that cures will soon be found for various diseases which afflict mankind through this legislation.
Rather the opposite seems to be the case when cells required for ongoing investigation into cures through medical science can take place through cells obtained in other ways from human bodies and certainly not through the creation of animal-human embryos.
I contend that matters of such concern to the peoples of our countries should not be left quite simply to a vote by members of parliament.
Along with my colleagues in England and Wales and my brother bishops here in Scotland, I would maintain that the establishment of a single permanent statutory national bioethics commission is something which would indeed bring considerable benefits.
As I indicated recently in a letter to the prime minister: "This would appear to be the only way that the issues raised by the swiftly developing biotechnology industry can be adequately discussed and weighed up in a body which engages with public concerns and informs the government and parliament on matters which will continue to raise such unimagined and complex ethical questions."
Our voice must be heard and that voice must be listened to especially by the members of parliament who will soon vote on this issue in the House of Commons.
Our Church, and I personally, have ... done all the "right things"
Sadly many members of parliament do not seem concerned - or rather are in a certain ignorance of what is going to happen.
In January of this year our Catholic Parliamentary Office wrote to all of Scotland's 59 members of parliament asking them how they intended to vote.
As of today only nine have bothered to reply.
Over three weeks ago Bishop Philip Tartaglia of Paisley wrote to Gordon Brown urging him to allow all his MPs a free vote - as of today he has not even had an acknowledgement!
Our Church, and I personally, have, I think, done all the "right things".
We have responded to the consultation document; we have sent letters to all of Scotland's members of parliament; we have written to the prime minister; we are speaking publicly about what is going on in our name and in our country.
Further, I recently signed a letter with other church leaders which concluded: "This bill goes against what most people, Christian or not, reckon is common sense. The idea of mixing human and animal genes is not just evil. It's crazy!"
Today as we celebrate in the resurrection the triumph of life over death I urge you to ensure that life continues to triumph over these deathly proposals.
I know that many of you have already made your views known to your members of parliament. I ask you to continue to do that.
Being a Christian and acting as a Christian must be one and the same thing.
Gathered here on this Easter Day we realise that we are indeed followers of Jesus Christ and with that comes responsibilities.
One of those responsibilities is, as I have indicated, to be "missionary".
May God indeed help us all to be missionary at this present time and to hand on the saving message of Jesus Christ in a world which does not seem prepared to receive it.