The Big Bang: Financial Deregulation

The Old City of London

Before 1986, the City of London operated like a gentleman's club. The London Stock Exchange had fixed minimum commissions — brokers charged what the exchange dictated, not what the market would bear. There was a strict separation between 'jobbers' (who made markets in stocks) and 'brokers' (who traded on behalf of clients). Outsiders — particularly foreign firms — were largely excluded. Trading happened face-to-face on the exchange floor. It was a cozy, insular, and inefficient system that had barely changed since the Victorian era.

By the early 1980s, it was also falling behind. New York had deregulated brokerage commissions in 1975 and was attracting business that might otherwise have come to London. Tokyo was rising as a financial center. If the City did not modernize, it risked irrelevance.

Thatcher's government negotiated an agreement with the Stock Exchange: in exchange for dropping an antitrust case, the exchange would abolish fixed commissions and open ownership to outsiders. The changes took effect on October 27, 1986 — a date immediately christened 'the Big Bang.'

What the Big Bang Changed

The reforms were sweeping. Fixed commissions were abolished, meaning firms competed on price for the first time. The separation between jobbers and brokers was eliminated, allowing single firms to both make markets and trade for clients. Foreign ownership of exchange member firms was permitted — and within months, American, European, and Japanese banks had bought up most of the old British firms. Electronic trading began replacing the physical trading floor.

The effects were transformative. The City of London became the world's leading international financial center — not because it was the largest domestic market (New York held that title) but because it was the most open. By the 2000s, London handled more international bank lending, more foreign exchange trading, and more international bond issuance than any other city. The financial services sector grew from about 6% of British GDP in 1986 to over 10% by 2007.

Employment in the City boomed. A new class of highly paid financial professionals emerged — traders, investment bankers, and fund managers earning salaries that dwarfed those in manufacturing or public service. The City became a symbol of Thatcherite aspiration: competitive, meritocratic (at least in theory), and enormously profitable.

London vs. the Rest

Perhaps the most lasting consequence of the Big Bang was geographic. As the City boomed, it sucked talent and investment toward London and the South East. The gap between London's economy and the rest of Britain widened dramatically. By 2016, GDP per capita in London was more than double that of Wales, the North East, or Northern Ireland.

This geographic inequality became politically explosive. The communities left behind by deindustrialization — the same communities devastated by pit closures and factory shutdowns — watched London prosper from an economy that seemed disconnected from their lives. Many historians trace a direct line from Thatcher's Big Bang to the regional resentment that fueled the Brexit vote in 2016.