HookThe first run on a British bank in 141 years
On 14 September 2007, queues formed outside branches of Northern Rock — the first run on a major British bank since Overend, Gurney & Company collapsed in 1866. The strange part: Northern Rock had no exotic trading floor and little direct exposure to America's toxic mortgages. It was a Newcastle mortgage lender with a fragile funding model — it financed roughly three-quarters of its lending not from customer deposits but by borrowing short-term on wholesale money markets. When those markets froze in August 2007 as subprime fear spread, Northern Rock could not roll over its borrowing. The Bank of England stepped in as lender of last resort; the news of the rescue is what actually triggered the queues; by February 2008 the bank was nationalised.
Everything in 4.5 is in that story. Banks borrow short and lend long, which makes them permanently one confidence shock away from a run. The financial sector is the economy's plumbing, so when it fails, everything fails with it. And the line between quantifiable risk and genuine uncertainty — the distinction this section opens with — is precisely the line the entire global banking system got wrong between 2003 and 2008.
ModelRisk versus uncertainty — the distinction that broke the models
Risk is quantifiable: you do not know the outcome, but you know the odds. Insurers price car crashes, house fires and flight delays from decades of claims data — that is risk, and markets handle it well through insurance, diversification and hedging. Uncertainty, in the sense economist Frank Knight nailed down in 1921, is unmeasurable: no probability can honestly be attached, because the event sits outside past experience. Pandemics, financial panics, a war rewiring energy markets — these are uncertainty, and no spreadsheet converts them into a premium.
Firms manage risk constantly: insurance transfers it, diversification spreads it (conglomerates smoothing the cycle across product lines), hedging locks it — airlines fix fuel prices with forward contracts, exporters lock exchange rates months ahead. The catastrophic mistake is treating uncertainty as if it were risk. Pre-2008 banks modelled mortgage default probabilities from decades of data in which US house prices had never fallen nationwide — so their models literally could not price the event that then happened, and correlations that looked safely low went to one overnight. When an exam question hands you a firm 'managing risk', check first whether what it faces is actually risk at all; spotting mislabelled uncertainty is a genuine evaluation point.
MechanismWhat the financial sector actually does
Strip away the towers and the sector does five jobs. Financial intermediation: channelling millions of small, short-term savings into large, long-term loans — mortgages, business investment — that savers would never make directly. Liquidity: letting you hold wealth you can spend instantly while the system lends it out for 25 years; this maturity transformation — borrow short, lend long — is the sector's core trick and its congenital weakness, because if enough depositors want their money simultaneously, no bank on earth has it to hand. The payments system: the invisible rails of salaries, direct debits and card transactions, without which commerce halts in days. Risk markets: insurance, forwards and futures that let firms shed risks they are not equipped to carry. And capital markets: shares and bonds connecting firms that need funds to investors who have them.
One more mechanism matters for the exam: banks do not merely recycle existing savings — when a bank makes a loan, it creates a new deposit, expanding credit and the money supply. That credit creation is why bank lending standards ripple through the whole economy, and why a credit crunch — banks refusing to lend — strangles firms that never touched a risky asset in their lives.
MechanismThe central bank — the system's anchor
The Bank of England, independent since 1997, wears three hats. Monetary policy: the nine-member Monetary Policy Committee sets Bank Rate to hit the 2% CPI inflation target, backed since 2009 by quantitative easing. Financial stability: the Financial Policy Committee watches the system as a whole, stress-testing major banks annually against imagined catastrophes — deep recessions, house price crashes — while the Prudential Regulation Authority supervises individual banks' capital and liquidity. Lender of last resort: when a solvent institution faces a liquidity crisis, the Bank lends against collateral to stop panic becoming collapse — Northern Rock in 2007, and again in September 2022 when the Bank pledged up to £65bn to stabilise the gilt market as pension funds hit trouble.
The lender-of-last-resort role carries the section's best evaluation concept: moral hazard. If banks believe rescue is guaranteed, they are subsidised to take bigger risks — heads they win, tails the taxpayer loses. That is why the safety net comes wrapped in regulation: higher capital requirements, ring-fencing of retail banking from investment banking (in force since 2019), and stress tests are the price of the implicit guarantee. A strong answer holds both thoughts at once: the anchor prevents panics, and the anchor breeds the risk-taking that makes panics more likely.
CaseThe Global Financial Crisis — the chain, link by link
Learn the GFC as a causal chain, not a montage. Cheap credit after 2001 met a US mortgage machine selling loans to borrowers with weak credit — subprime. Securitisation bundled thousands of these mortgages into mortgage-backed securities and CDOs, sliced, rated (often AAA) and sold to banks worldwide — risk was not reduced, just relocated and hidden. When US house prices turned down in 2006–07, defaults rose, the securities' values collapsed, and because nobody knew who held the losses, banks stopped lending to each other: the credit crunch. Northern Rock's funding evaporated in 2007; Lehman Brothers failed on 15 September 2008; days later RBS — briefly the largest bank in the world by balance sheet, around £2.2 trillion, bigger than the UK's annual GDP — was hours from collapse. The taxpayer injected £45.5bn into RBS alone; total UK support peaked at roughly £137bn in cash with guarantees above £1 trillion. UK GDP fell about 6% peak to trough, and the aftermath — Bank Rate at 0.5%, £375bn of QE by 2012, years of austerity — shaped a decade.
The regulatory answer targeted each link: capital requirements up, ring-fencing to insulate retail deposits, annual stress tests, and a shift to macroprudential thinking — watching the system, not just each firm.
Why did falling house prices topple whole banks? Leverage. Take a bank with £100bn of assets financed by £4bn of shareholders' equity and £96bn of borrowing — a capital ratio of 4% (4 ÷ 100), or leverage of 25:1. If its assets fall just 4% in value, the loss is 100 × 0.04 = £4bn: the entire equity is gone and the bank is insolvent. Several pre-crisis banks ran leverage above 30:1, where a ~3% asset fall is fatal. Run the same arithmetic with £10bn of equity (10% capital) and the bank survives the identical shock with £6bn to spare — which is the entire logic of post-crisis capital rules in four lines of arithmetic.
VocabularyKey terms the mark scheme pays for
TrapsMisconceptions that cost marks
ExamWhat examiners want
Chronology is marked: Northern Rock (September 2007) came a year BEFORE Lehman (September 2008), and muddling the order signals a memorised montage rather than a causal chain. Structure any GFC answer as links — cheap credit → subprime lending → securitisation → mispriced risk → leverage → contagion → credit crunch → real-economy slump — and make each arrow do explanatory work; examiners reward the candidate who explains WHY one link forced the next.
Keep two distinctions surgically sharp: liquidity versus solvency (Northern Rock versus RBS is the perfect contrast pair) and risk versus uncertainty. On any bailout or lender-of-last-resort question, moral hazard is the evaluation spine — rescue prevents contagion today but subsidises recklessness tomorrow, which is why capital rules, ring-fencing and stress tests came attached. Anchor with two or three defensible numbers: £45.5bn into RBS, Bank Rate cut to 0.5% in March 2009, UK GDP down roughly 6% peak to trough — hedged approximations quoted confidently beat precise-sounding inventions.