Hold the line! Stay with me! Hold the line! That is the thrilling cry of the heroic Roman general Maximus as he leads his men into battle in the film Gladiator. I have watched it many times with my son and every time my inner child has responded to this exciting Hollywood call.

These days, and not least last week, I often think that we as a society have lost the determination to hold the line in defence of common sense and shared values against stupidity, dishonesty and external threats. Take the thin blue line which the police are supposed to hold against lawlessness.

Last week it emerged that the police have willingly, and sneakily, broken that thin blue line themselves, at least in Gloucestershire where the constabulary rejected 108 potential recruits purely because they were white and male, in the name of promoting diversity and advancing women and ethic minorities instead. The fact that they did so in an attempt to follow government guidelines only makes it worse.

Last year Gloucestershire constabulary had advertised for recruits, secretly determined to select as many women and minority people as possible; as a result every female or ethnic minority applicant was chosen for the second round while two-thirds of the white male applicants were rejected. Even so, 171 white men, despite their undesirable race and sex, did make it through to the second round. But soon afterwards 108 of them were mysteriously told they had been “randomly deselected”.

That must be untrue. They had been deselected not “randomly” but precisely because they were white males; I suppose it may be true that the choice of which white males to “deselect” within the group was made randomly but that is hardly the point. On the thin blue line, race and sex were seen as more important than merit.

Fortunately, lunacy has not yet taken over entirely. A Bristol industrial tribunal did pronounce last week that Gloucestershire constabulary had been “at the very least disingenuous and at worst misleading” by unlawfully discriminating on grounds of race and sex. The force apologised, saying it was only trying to advance diversity and had thought this was “lawful, positive action”. You can hardly blame it; this whole subject is riddled with doublespeak. There is a deep dishonesty about the government setting targets but rejecting “quotas” as illegal. It is hard to spot the difference. Gloucestershire Plod thought he was under pressure to meet a government target to get ethnic minority recruits up to 7% of the total by 2009. Last year the figure was 1.6%.

What is so ludicrous about all this is that Gloucestershire has the fewest ethnic minority people of almost anywhere in Britain. A Guardian newspaper map of multicultural Britain shows no significant groups of ethnic minorities in the area at all. According to the Gloucestershire force’s own figures, the proportion is only 2.8%. Besides, it is highly contentious that every group (women, minorities, homosexuals or redheads) must be represented in every occupation in exact proportion to its numbers in the general population.

It may well be that the tiny number of West Country Sikh women, or Chinese men, don’t actually want to be police officers. They might have cultural reasons which dissuade them and surely we are supposed to respect such cultural diversity.

What, in this lamentable story, is this guilty obsession with race, this daft and patronising determination to exclude and demoralise the indigenous people? It is actually imposed in Gloucestershire by people who are mostly white males themselves. What is wrong with them? Why are they unwilling to hold the line against thoughtless, intrusive, guilt-ridden, destructive stupidity? One word for it is self-hatred. Another is decadence.

It is for the same reasons, whatever they may be, that we are so obviously failing to hold the line against the extremes of Islam. We no longer carry high the standard of free speech for fear of offending people, usually Muslims. Stalwart citizens have recently felt it their duty to reprimand the Pope and a former Archbishop of Canterbury for discussing Islam and violence — for even raising such offensive questions.

The results, for which we have only ourselves to blame, are alarming. Anyone who heard it must have been horrified by a British Muslim haranguing John Humphrys on Radio 4’s Today programme on Friday. Abu Izzadeen, the Jamaican convert who had heckled the home secretary at a meeting with Muslims, sounded even more terrifying on the air. Aggressive, illogical and blustering, he expressed his hatred of our government and its “crusade” against Muslims. He thinks free speech and democracy are incompatible with Islam.

When Humphrys asked him what was wrong with democracy, with trying to change things through Britain’s democratic process, he replied that “democracy means sovereignty for man, Islam means sovereignty for sharia . . . The UK doesn’t belong to you, it belongs to Allah”, and Allah has put Muslims on earth to implement sharia (Islamic law). So, Humphrys insisted, “the Islamic process but not the democratic process?” “Yes,” said Izzadeen confidently, “that’s right.”

It would be comforting to assume that Izzadeen is solitary and ignorant. Unfortunately he isn’t. An NOP poll for Channel 4 found that almost one in four British Muslims believed that the slaughter in London on July 7 was justified. Muslim community leaders can say what they like about Islam being all about peace; it’s perfectly clear that not all Muslims see it that way. For a long time now they have spread rage and resentment among their people and we have lacked the will and the instinct for self-preservation to resist it.

We all know what happened to Maximus. For all his strength and honour, for all that he tried to hold the line in his country’s interests, he came to a sticky end because Rome was by then decadent, demoralised and rotting from within. It may seem extreme to compare contemporary Britain and the Gloucestershire constabulary, or the mouthings of an irrational Muslim convert, with the latter days of the Roman empire. But it’s worth a thought.

Times Recommends

• It’s the beginning of the affair
• Afghanistan: still a price worth paying
• Heroes of the downtrodden