The term "credit crunch" is used loosely to describe an economic downturn, that might become a full-blown recession, and which indeed is linked in part to a shiftless lending of money to people who can't pay it back. If there is an economic slide, with job-losses from what is now a majority service-economy, this will impact further on the service-sector causing further job-losses. If people have less spare cash to spend, on retail and other "services", workers in these industries will begin to be laid-off. There will be less people working and thereby contributing tax to the government's coffers and more drawing benefits from them. It has been said that the anticipated level of public-sector (i.e those who work for the state) pensions is such that it could bankrupt the nation - add too the burden of increased welfare payments to a swelling number out of work, with fewer working shoulders to bear that load, and we are in trouble indeed.
The French have similar problems in respect to pensioning their state-workers, who were promised very generous deals after the second world war, for instance to run the transport infrastructure, fire-service, postal-service etc., but which are no longer affordable within their present situation. There has been a certain level of industrial action over all of this, and I have little doubt there will be similar in Britain too. However, the bottom line is no matter how loudly the unions or anyone else may shout for more, if the money to prop-up these various systems is not there, they will fail, and money taken from elsewhere, as must be necessary to do so, merely shifts the hardship somewhere else. There seems to be a case for economic efficiency as for energy-efficiency along the lines that you can't squeeze blood from a stone. "Agreement" must prevail in the longer run but for now it will be the "boss-class", "them and us" politics that tries its hand, and which in the 1970's brought Britain to such a state of discontent with the Labour party and the trade unions, that Margaret Thatcher's government were elected in a land-slide majority, to much regret afterwards, since she destroyed the recalcitrant and militant trade-unions by crippling the industries without whom they had no power. Hence much of our present industrial weakness and dependence upon the above referred to "service-sector".
Whatever the subtle rhetoric of industry and pension arrangements, there are emerging dire (but unsurprising, really) predictions about the consequences of the "credit crunch". Now arguably Britain is on a social knife-edge (forgive the unintentional pun in the face of rising violent crime among young people who have been "parented" to have little actual sense of belonging, purpose or self-esteem), and it is only the benefits "giro" that keeps things in some semblance of order rather than anarchy. This may change, however, once the government can no longer maintain the "keep them quiet" payments.
Here are some thoughts inspired by a couple of recent articles [1,2]. A crime-wave is expected, as times get hard, with increasing intolerance toward immigrants. The latter notion follows presumably the lines of the "them taking our jobs" antipathy, but ironically "they" are apparently needed "to do the jobs our own people won't do". This does strike me as paradoxical, to pay people to do nothing so they are in the position of choice of "won't do", while we bring in foreign labour and pay them on top. Surely there is some compromise system possible, i.e not to pay anyone slave-wages, but rather to ensure that all who are "British" make a constructive contribution to society, by topping-up when necessary (and the employer is not simply trying to behave like a slave-master) the wage to a reasonable amount.
This approach would strike at the heart of the pernicious "benefits culture", and save the government an awful lot of money. When energy, particularly fuel is hugely expensive we will have plenty of work to do (much of it manual, on farms and in other crafts) and it will not be practical or cost-effective to simply bring-in labour from abroad whose taxes pay to support our own unemployed people. This is the beckoning age of national self sufficiency which it would be laudable to anticipate rather than pretend that our current way of life can be continued so wastefully.
Family breakdown  is another aspect expected to be "triggered" by the impending economic crisis. This has already happened to such as degree in Britain that it sounds hollow and false to refer to it as some forthcoming event. Half of all marriages end in divorce and many do not get formally married. That is of course a matter of personal choice, but it makes it impossible to quantify the degree of "family breakdown". At one time we talked about "broken homes" in the implication that the home was the stable norm and the breaking of it an infliction on the national social fabric. More likely the "non-nuclear family" (to be PC) is now the norm and a major contribution to why kids are left without a sense of belonging, purpose or self-esteem. It then becomes the state or the gang that surrogates the vital role of parent. Will more families break-up, in the face of bankruptcies, home repossessions, unemployment and a generalised struggle to pay household bills? Perhaps; but underpinning this potential strife is a safety-net that has become a device; a culture that does not allow for improvement and which condemns those entrapped in it.
Whatever happens to our personal finances, we must begin the restructuring of society to foster a sense of social integrity and the opportunity for all to contribute to the land that will be ours in both five years and five generations. This is surely the age of the transition-town: toward a community that is sustainable both in energy and in all other needs, as human beings, believing ourselves and each other worthwhile.
 "Credit crunch could lead to crime wave, Home Office warns Downing Street." By Andrew Porter. http://www.telegraph.co.uk/news/newstopics/politics/lawandorder/2657335/Credit-crunch-could-lead-to-crime-wave-Home-Office-warns-Downing-Street.html
 "Deepening economic crisis 'may trigger family breakdown'.By Becky Barrow. "http://www.dailymail.co.uk/news/article-1048935/Deepening-economic-crisis-trigger-family-breakdown.html