Production at Britain's largest undeveloped oil and gas field, Rosebank, has hit a snag after someone accidentally dropped some critical drilling equipment into the North Sea. Because nothing says 'energy security' like a safety valve taking a 1,100-metre plunge to the seabed.

The incident, which occurred on April 18, involved two pieces of central drilling gear - including that all-important safety valve - taking an unscheduled dive. No workers were harmed, but the rig, leased from Norwegian company Odfjell Drilling, had to be shipped to a shipyard in Bergen for repairs. It's now back at Rosebank, about 80 miles north-west of Shetland, but still not operational.

Odfjell Drilling's internal docs suggest the rig could be out of commission for up to four months, meaning some oil wells will be completed significantly behind schedule. So much for that pre-Christmas oil rush.

Adura, the company behind Rosebank, now says oil production won't start until sometime in 2027 - a far cry from the end of this year, as previously hoped. The field is projected to yield 300 million barrels over 25 years, but that's little comfort for winter energy supplies.

The delay comes as the new government, led by Andy Burnham, faces pressure from the fossil fuel industry to greenlight Rosebank, despite opposition from climate campaigners and some Labour MPs. The new energy secretary, Miatta Fahnbulleh, is expected to make a decision after consultations on emissions conclude in August.

Meanwhile, the smaller Jackdaw site, about 150 miles east of Aberdeen, could start pumping gas as early as October, according to Adura. But don't get too excited - an environmental impact assessment reveals Jackdaw would create a whopping 27 direct full-time jobs. Twenty-seven. For one of the biggest remaining gas fields.

Ed Miliband, now foreign secretary but formerly a vocal critic of Rosebank, once called the plans 'climate vandalism'. Now, whispers suggest talks are underway on how to allow new drilling without breaking Labour's 2024 manifesto pledge to honour existing licences but issue no new ones.

Environmental groups are sharpening their legal pencils, considering whether to challenge any approval. Angeliki Papantoniou, a lecturer in environmental law at the University of Hull, says a fresh challenge would be a 'long shot' but could succeed if based on 'substantive environmental matters' like ecosystem disruption and pollution.

Areeba Hamid of Greenpeace, which already challenged the original licence grants, argues approval would make 'zero difference' to energy bills and generate few jobs. 'Despite these meagre benefits, we would be prolonging a polluting industry that's fuelling heatwaves while sending a disastrous signal to our international allies,' she said.

Odfjell Drilling declined to comment. Adura did not respond to a request for comment. So, for now, the dropped gear sits on the seabed, and the UK's oil dreams are, well, on hold.