Before she died, my wise grandmother, who gently led me into the Christian faith ahead of my attending university, warned me against getting involved with the Christian Union (CU). Margaret was an Anglo-Catholic traditionalist who wore her religion lightly, and I imagine she must have feared what she saw as the pushy approach of the evangelical movement.

Nonetheless, I suspect that she would join me now in being dismayed at the decision by the Junior Common Room of Oxford University's Balliol College to ban CU representatives from attending the college's freshers' fair over concerns at the 'potential for harm to freshers'.

For according to Oxford's student newspaper Cherwell, the student body wanted the freshers' fair to be a 'secular space', though eventually the CU was told that it could display leaflets at, but not attend, a single, multi-faith stall.

In other words, the real principles of liberal democracy – not to mention those of treating students like adults – were discarded and a value judgement about the merits of secularism was imported into the College by its JCR.

The JCR's vice-president Freddy Potts, and its president Hubert Au, wrote clever-clogs emails to the CU which were seen by Cherwell.

Potts reportedly wrote: 'We recognise the wonderful advantages in having CU representatives at the freshers' fair, but are concerned that there is potential for harm to freshers who are already struggling to feel welcome in Oxford.'

In a curious summary of the record of the faith which is facing the most discrimination of any around the world, he added: 'Christianity's influence on many marginalised communities has been damaging in its methods of conversion and rules of practice, and is still used in many places as an excuse for homophobia and certain forms of neo-colonialism.'

Potts is clearly so fashionable that he failed to see the irony in the way in which Christianity was being 'marginalised' by his decision. As for 'homophobia and certain forms of neo-colonialism,' the role of, say, some forms of Islam appeared not to cross Potts's doubtless big brain.

Meanwhile, in a Facebook post, Au said that the decision to have a multi-faith stall rather than a specific CU stall, was reached 'in light of both concerns raised by members [of the Welfare sub committee] and by an undergraduate survey conducted last term, which indicated a lack of familiarity as to where non-Christian societies, events and services were located'. He added: 'We didn't want to monopolise the presence of any individual faith/belief society at the Balliol freshers' fair.'

It appears to be unclear whether there was a demand from other faiths either to ban the CU or indeed to have any presence at the fair themselves. But it seems bizarre to see a CU presence as Christianity being allowed to 'monopolise'.

Perhaps Freddy and Hubert practise a non-Christian faith themselves, but my guess is that the demand demonstrated in the undergraduate survey, such as it was, came from fashionable non-believers more than it did from those practising other faiths.

The key revelation here is the desire for a 'secular space,' which is so in line with the trend in the political world of Westminster, where the former Liberal Democrat leader Tim Farron was earlier this year thrown to the lions over his evangelical Christianity.

Oxbridge, which produces so many politicians, loves to mimic the Westminster Parliament, with endless motions of no confidence in the government and other political debates.

But a serious university college should of all places be one of free thought, with grownups being allowed to choose, as I did, whether or not to engage with the CU and any other body. Of course, there is something patronising about the assumption that people cannot make up their own minds.

As Nigel Genders, the Church of England's chief education officer, has said: 'Freedom of religion and belief is a fundamental principle that underpins our country and its great institutions and universities... [To exclude CUs] in this way is to misunderstand the nature of debate and dialogue and at odds with the kind of society we are all seeking to promote.'

Sadly, however, if it becomes normal to ban a Christian presence at universities, while traditional Christian views are increasingly marginalised at Westminster, the sun may be setting on that 'kind of society'.