The scale of the decline in global markets was truly astonishing. On what has already become known as "Black Friday", the FTSE 100 fell nearly 9%, closing below the 4,000 mark for the first time in five years. The Dow Jones in New York fell by 600 points within minutes of opening; though it staged a recovery, by close of business it had plummeted more than 18% in its largest ever weekly fall.

Over the week, £2.7 trillion – a staggering sum – was wiped off the value of global shares. Bad news for city fat cats, yes. But also bad news for anyone whose pension or endowment mortgage is dependent on the stock markets. Bad news for everyone living in economies which are teetering on the brink of recession and could yet pitch into full-blown depression.

As we report today, the pain is coming to us all, and it will not so much trickle down as pour down. Credit has dried up and consumer confidence is low, so business failures will rise. Economists predict that unemployment will rise by nearly 34% next year; that's another 38,000 Scots who will be struggling to make ends meet. Many will add to the benefits burden carried by a smaller number of income tax payers.

Taxes will inevitably rise too. Not immediately, as the government relies on borrowing to offset the worst of the downturn. But, as sure as night follows day, we will all pay the price as that debt is serviced and repaid, while public services are maintained. Several local authorities may have to raise council taxes if their investments in failed Icelandic banks are lost.

So, make no mistake, we should all care about the crisis – and we should be alarmed at the inadequate response of world leaders, too. Finance ministers of the G7 group emerged from a lengthy summit yesterday to announce a five-point plan which vowed to stop banks failing, help them raise funds, get credit moving, safeguard savings and boost mortgages.

Well thanks, gentlemen (and lady). But how? The trotting out of such bland generalities revealed the G7 meeting for what it was – a photo-opportunity. No new grand plan or detail was forthcoming, nor was it ever on the agenda. Instead, the five-point plan provided political cover for the various individual actions of each nation. That's why George Bush spent just a half-hour at the talks and why he then had nothing of consequence to say. The impression of a rabbit caught in headlights grows ever stronger.

Here in Britain, the irony of the 'Brown Bounce' being enjoyed by the Prime Minister will not be lost on anyone who notes that he spent 10 years in charge of the economy. But Gordon Brown has looked like the world leader most in command in these troubled times. The £500bn plan he devised with senior bankers and Alistair Darling came closest to finding a coherent way out of this crisis. That one nation's efforts were not enough to halt last week's slide was hardly their fault, though yesterday US Treasury Secretary Henry Paulson effectively backed their plan when he said his own bank bailout would now focus on buying shares in banks.

This is a start, but more is needed. As the co-ordinated drop in interest rates briefly showed last week, joint global efforts can work. At the very least, they increase confidence that someone is in charge of the situation. With those dealing in shares currently behaving like lemmings, world leaders need to show the same shared determination to safeguard the financial institutions on which the global economy and individual depositors and borrowers depend.

This needs joined-up efforts to increase liquidity – and they should have been arranged before the markets open tonight and tomorrow. We can only hope that this failure is not too damaging, and that decisive, stronger action will come. When the worst is over, our Government will need to pick up the casualties and get them back on their feet; it must also lead global attempts to stop anything like this happening again.