PETROL delivery trucks were once again rolling from the gates of the Coryton oil refinery in Essex today after a shutdown triggered when the site collapsed into administration - but unions were braced for news of job losses at the plant.

The refinery’s administrators, PwC, said after discussions with suppliers and customers, who include BP, that they had started shipments of refined oil products with immediate effect, easing fears over fuel shortages.

The site, which supplies 20% of fuel in London and the South East, halted sales after its Swiss owner Petroplus placed the refinery into administration, prompting fears of up to 1,000 job losses.

BP is understood to be the refinery’s biggest customer but previously said it had not suffered from any immediate supply issues.

The formerly BP-owned refinery had been operating as usual otherwise, but with no deliveries of petrol or other products, including bitumen, leaving the site.

While deliveries have started again, PwC was unable to confirm whether the shipments were running at full capacity.

And Coryton staff were told to expect some job losses, union sources said, although administrators are confident of finding a buyer.

A ship was due to dock this morning to unload 600,000 barrels of crude oil, the union official said.

PwC, which is also dealing with the administration of two other locations – an oil storage site in Teesside and a research and development site in Swansea – said Petroplus had suffered as a result of “low refining margins and high restructuring costs”.

The market has become tougher as the economic downturn in Europe has hit demand for transport fuels and competition has grown from the refineries in Asia.

Petroplus reported a net loss of 413million US dollars (�265million) in the first nine months of last year, while in December its banks withdrew a 1.05billion US dollar (�675million) portion of its 2.01billion US dollar (�1.29billion) credit facility.

There are seven other refineries in the UK - at South Killingholme and Lindsey, both in north Lincolnshire; Fawley, near Southampton; Grangemouth, near Falkirk; Stanlow in Cheshire; and Milford Haven and Pembroke, both in Pembrokeshire.

The other main supplier for the South East and London is the Exxon Mobil refinery at Fawley.

A meeting is expected later today involving the administrators, the Government and unions as part of efforts to secure the refinery’s future.

A GMB official said last night: “The administrators told union members that they consider the site to be viable and that they would continue to operate it, albeit with some cut-back in jobs.”