What causes a third of the cabinet and one in five ministers to break ranks and campaign against their own government? Is it faith academies, a massacre in Iraq, or the suspension of habeas corpus? None of these. Go out into the highways and byways of the nation and ask what moves the political soul at present. It is the threatened closure of some 2,500 local post offices.

Open any local paper and it is a raging obsession. That is why Jack Straw, Jacqui Smith, Geoff Hoon, Andy Burnham and others agreed with Patricia Hewitt when she ordered the closures as posts minister and then pretended that they did not mean it. Like those now professing to have been "really" against the Iraq war, they represent the new virtual politics of hypocrisy.

There is something about post offices that has Don Camillo and Peppone marching arm in arm. That grubby counter at the back of the shop holds the arcane mysteries of forms V14 and V890. It can unlock the code of DVLA/V10, Transcash, Smilers and the whole haberdashery of the general post. The village post office evokes the age of Hovis and prison mailbags, of bicycle clips and little red vans. It is the Miss Marple public service, the acceptable face of nationalised industry.

Inside is the time-hallowed communion of the counter queue, shuffling eternally towards the altar of the state, to sip the bread and wine of entitlement. These queues embody Britain's love/hate for authority. They meld the citizen into a stomping, muttering chorus of complaint, into Tennyson's "a thousand peering littlenesses".

Some time ago the California town of Carmel (one-time mayor, Clint Eastwood) went in the opposite direction from Britain. It stopped home postal deliveries, except by volunteers to the severely disabled, and ordained that citizens collect mail from the post office on 5th Avenue. The reason was explicit, to generate a habit of using the office and create a haphazard, neighbourly town meeting, a latter-day Athenian agora.

In Britain such social engineering would be regarded as a sin against target-driven centralism, and probably communist to boot. Instead closure mania is gripping every corner of Britain's public service, and people do not like it. The government has shut almost half of all post offices, from 21,000 to 12,000, of which only 6,500 are said to be "profitable". The remainder require a subsidy of £150m, which is less than the professional fees on a single government hospital contract.

In some cities the result is astonishing. In London 169 closures are planned, saving just £3m, leaving the entire W14 area of Hammersmith (the size of Canterbury) without a single office, and W9 with just one. The threat to Maida Vale's Formosa Street office has evoked the sort of fury that greets the closure of a West End theatre.

Nor is it just post offices that vanish. In the past 10 years the number of police stations fell by over 20% and a further 40 are threatened, including 13 in London. Wiltshire plans to have just four stations left in the county. Rural areas have lost not just their police stations but their village police houses.

In the realm of primary schools, a fixation with parental choice and a terror of sacking bad staff is leading to a sudden rash of closures. In England and Wales, more than a thousand are now planning to shut, in many cases because parents are driving their children to schools miles away when a council fails to improve a local school. Shropshire wants to close 22 schools and merge another 16. Gwynedd in Wales wants to close 29. Nobody stops to ask what the "car miles" cost of this policy might be.

Chaotic planning in the NHS makes it near impossible to know the number of local district and cottage hospitals facing closure at any one time. A 2006 white paper pledged to "create many new cottage hospitals" - some 50, at an allotted £750m - at the same time as a pledge to close up to 90 of 360 English cottage hospitals. The extra-50 pledge emerged as a Downing Street spin exercise.

There is no way of measuring the impact on communities of thus ripping out their institutional memories and meeting places. It must be savage. Each plays its part: school, hospital, surgery, police station, post office. Some statistics speak for themselves. Since 1997 the number of schools with fewer than 1,000 pupils has fallen by a fifth, while that of super-size secondary schools (more than 1,500 pupils) has more than doubled, resulting in a 28% rise in permanent exclusions, or three times the rate for small schools. Big is plain bad.

Levels of public fear and a perception of town centre anarchy have risen with the loss of a police presence. The concentration of services saves the NHS money (supposedly), but imposes travel and insecurity costs on patients and their families. The growing need to take a bus or car to visit a post office is time-consuming and ecologically stupid.

Some fightback is beginning. The "closure culture" has produced an upturn in just-in-time politics. The nation is awash in marches and protests in defence of local institutions. A march by 7,000 people in Haywards Heath saved an accident unit. Yesterday Victoria Wood threatened to chain herself to a postbox in north London.

Essex won plaudits for offering to take its threatened post offices off the government's hands and merge them with council "one-stop shops". In Leicestershire's Sheepy Magna, £45,000 was raised to put a post office into the local parish church. Pershore in Worcestershire has decided to build its own hospital rather than wait on Whitehall.

Gordon Brown's concept of a public service as a gigantic, self-contained and unaccountable "business model" is clearly inappropriate to social Britain and is deeply unpopular. Hazel Blears, the so-called communities minister, has not lifted a finger in protest. Yet having voted for hospital closures, she herself turned tail and campaigned against them when they hit her Salford constituency.

The government's Orwellian hostility to the institutional identity of British communities can only promote alienation and indiscipline. It turns communities into bleak, car-reliant dormitories, devoid of places of casual association. It removes the informal leadership of the resident teacher, doctor, police officer, shopkeeper. What central government may think it saves in the general, it loses in the particular. It is in the particular that people live.

simon.jenkins@theguardian.com