But no more. You will search in vain in their recent output for anything to inform you as a Christian of what is going on in culture around family, marriage and sexuality or to equip you in your workplace or your children's school to respond biblically. What has happened?

LICC was founded in 1982 by leading evangelical teacher John Stott to, in his words, 'relate the ancient Word to the modern world'. His vision was for Christians to 'integrate' all areas of life under the Lordship of Jesus and thereby to 'penetrate the secular world' with 'a more integrated gospel'.

Today LICC is committed to: 'Empowering Christians to make a difference for Christ in our Monday to Saturday lives'. Yet a search of the Institute's output since January 2016--including their weekly Connecting with Culture email--reveals not a single article about marriage, family or LGBT issues. Not one. With all that is swirling about in our culture at the moment, and the immense pressure on Christians to abandon biblical standards on sexuality, how exactly is this empowering Christians for their Monday to Saturday lives?

LICC was founded by leading evangelical teacher John Stott to 'relate the ancient Word to the modern world'.

Perhaps LICC is specialising in certain areas and leaving these important matters to others? If so, then it seems to be an exception, as it runs articles about almost every other aspect of culture, from money to Marvel to fashion. In addition, there is no sign of LICC's support for the few Christian organisations which do still stick their necks out in these increasingly pressured areas, such as Christian Concern and the Christian Institute.

Instead, what do we find? A collaboration in a theology competition last Autumn--the Theology Slam--in partnership with liberal-leaning Lambeth Palace, Church Times and SCM Press. Entrants were offered twelve topics to choose from, none of which were family, marriage, sexuality or gender. Instead there was a selection of standard progressive concerns, including the 'gig-economy' and 'consumerism'. The three finalists spoke on #MeToo, the Environment and Mental Health. Are we beginning to form a picture of an organisation which limits itself to issues approved by Guardian readers?

The story is similar at the Jubilee Centre. Founded by Michael Schluter in 1983 to 'promote social engagement ... based on careful research' to 'change society in the direction of the biblical social model', up until 2013 it produced high quality resources on family and marriage. This included giving evidence to MPs in 2013 warning against the same-sex marriage bill.

However, since then, the organisation's resources in this area have become few and far between. It published one very tentative piece in 2016 on transgenderism which described itself as an opening comment, but there has been no obvious follow-up. The number of posts and articles in the past five years relating to family, marriage or sexuality could be counted on one hand--despite one of them rightly describing sex as 'a largely unspoken aspect of church life, which dominates our daily lives'.

One post rather oddly accuses the church of undermining marriage by over-valuing it, which is perhaps a 'lesson' the Jubilee Centre has taken too much to heart.

So what explains this silent night of Britain's evangelicals? The timing is surely a clue. The advent of same-sex marriage in 2013 was a watershed in our culture's approach to family and marriage. It was, for example, the last time Archbishop Justin Welby or any serving Church of England bishop spoke out in defence of Christian marriage.

Since then, the statutory equality of same-sex marriage and male-female marriage has paved the way for a relentless campaign by LGBT activists to erase any remaining distinctions in public or civic life, along with any remaining liberty to dissent. It has also been the catalyst for the next phase of the LGBT movement: the assault on the notion of biological sex itself in the transgender movement.

In this environment the cost of speaking out on these issues in terms of risk to reputation and splitting supporters has increased dramatically. Silence seems a prudent option, and comes with rewards of partnership with establishment players like Lambeth Palace and the Church Times, as LICC have discovered.

This self-muting also appears to be the approach of another (non-evangelical) Christian think tank, Theos, who have maintained a studied silence on all these issues, not commenting one way or the other, allowing them to maintain some standing with both liberals and conservatives.

This is a sad reflection of a Christian and evangelical world more divided than ever on sex and marriage, despite the Bible being as clear as day in its teaching on the matter. And it is yet another way in which same-sex marriage undermines the institution of marriage in society, by reducing many Christians to silence on it, even when they privately hold to biblical teaching.

The advent of same-sex marriage in 2013 was a watershed in our culture's approach to marriage.

Meanwhile, a solid defence of Christian teaching on marriage, sex and family is pushed ever further to the margins of polite society. Organisations which keep the faith are shunned not only by mainstream media and liberals but also by the silent evangelicals desperate to keep in with the fashionable crowd and avoid social ostracism, or indeed litigation.

I have no doubt that much of the work LICC and the Jubilee Centre do is worthwhile. But now is not the time for silence on the big issues facing Christians in our society. Biblical teaching, particularly on sex, marriage and family is under attack from all sides, and as much as ever Christians need to be equipped to have confidence in what the Bible teaches and to live it out and stand up for it in every area of their lives.

The culpable silence of organisations like LICC and the Jubilee Centre, while preferable to outright rejection of biblical teaching, reflects and magnifies a faltering of faith that is having a devastating impact on churches around the world. If evangelicals will not stand up for the Word of God and hold to it despite all that the world throws at them, then who will?

It is crunch time for biblical faith in the West as the progressive and secularist forces unleashed in the Enlightenment set their sights on the eradication of any public presence of orthodox forms of Christianity. Biblical teaching on marriage, sex and family is high among the charges against the faith. Now is the time for Christian organisations to arm the people of God to remain faithful, not to discreetly absent themselves from the fray and leave the dangerous jobs to others.

LICC and the Jubilee Centre were contacted for comment, but there was no response.

Dr Will Jones is a maths graduate with a PhD in political philosophy and author of Evangelical Social Theology: Past and Present [Grove, 2017]. He blogs at Faith and Politics