After a half-century of watching Norway turn North Sea oil into a $2.4tn national piggy bank, the United Kingdom has finally decided to try its hand at this whole sovereign wealth fund business. Chancellor John Healey announced the creation of an Energy Wealth Fund on Wednesday, seeded with £2bn diverted from the existing National Wealth Fund, at the same event where the Jackdaw gas field was approved.

The timing is impeccable, arriving in the same week that national debt hit £3tn for the first time. Nothing says fiscal prudence like launching a savings account while the mortgage is in arrears.

Healey himself acknowledged the elephant in the room, or rather the trillion-pound elephant that never was. "If we had done this when North Sea oil was first discovered in the 1980s, we'd have a British Sovereign Wealth Fund now that would be worth probably a trillion pounds," he said. Treasury officials, presumably with nothing better to do, actually ran the numbers for the first time. Their internal modelling assumed the UK's historical North Sea receipts of £200bn had been invested with no withdrawals, growing at a rate comparable to Norway's. The result: £1tn. A missed opportunity, one insider admitted, noting that "had we systematically invested those receipts, we could have built a huge national asset for future generations."

The "what if" has long haunted UK economic policy circles. Critics of the Margaret Thatcher era argue peak oil revenues were frittered away on pre-election tax cuts, which in turn were spent on 1980s garden conservatories. Others insist subsequent governments squandered the money on wasteful spending. Either way, the contrast with Norway is stark: its fund only began in earnest in 1996, and ordinary Norwegians can check its live value on the Oslo commuter train, where officials who run it are sometimes lambasted by fellow passengers. Three percent of its value is drawn down annually to fund a fifth to a quarter of government budgets, including during the coronavirus pandemic, and it is explicitly designed to fund Norway's post-oil economy. It is, in short, a gift to the future.

The UK's new fund will operate rather differently. Norway's is obliged to invest abroad and has grown enormously off the back of US big tech. The UK plan is to invest domestically in green energy, which may struggle to match that performance. UK energy tax revenues are also forecast to dwindle as North Sea production slows, though Jackdaw and extensions to existing fields may ease the rate of decline. Critically, Norway's state still controls its oil companies, giving it a share of their profits.

Norway's fund started with exactly two billion Norwegian Kroner 30 years ago and is now worth over a thousand times that. Nobody expects the Energy Wealth Fund's £2bn to be worth £2tn by 2056. The question remains: what might have been, had a similar far-sighted idea been adopted here decades ago? And more pressingly, how much gas could Jackdaw provide, and will it cut your energy bills?