--Coryton refinery workers stage protest, urging U.K. government to intervene

--Coryton closure would cost local and national economies over 100 million pounds ($155 million), council leader says

--Shell, Vopak and Greenergy believed to be preferred joint bidder, workers and union say

By Konstantin Rozhnov

LONDON--Employees of Petroplus Holdings AG's Coryton refinery in England and members of the Unite labor union Thursday staged protests in London, urging the U.K. government to intervene as the workers said the refinery has been idled.

Demonstrations took place outside the U.K. parliament, the Department of Energy and Climate Change and the office of Royal Dutch Shell PLC (RDSA).

Before Petroplus lost access to all its credit lines and then filed for insolvency in January, the 220,000-barrel-a-day refinery, one of the most sophisticated in Europe, was supplying around 10% of the U.K.'s fuel market.

Shell, Royal Vopak NV--the operator of three terminals in the U.K.--and fuel supplier Greenergy Ltd. are believed to be a preferred joint bidder for the facility, but they want to turn it into a terminal, said the Unite's regional industrial organizer Russ Ball and Coryton workers.

Meanwhile, a Russian company wants to buy Coryton as a refinery, which would save jobs, they added.

A spokeswoman for PricewaterhouseCoopers, the administrator of Petroplus's U.K. subsidiaries, said Thursday it doesn't comment on dealings with particular parties. Shell declined to comment. Vopak and Greenergy weren't immediately available to comment.

The Coryton refinery directly employs 500 people and provides jobs for a further 350 contractors, said John Kent, the leader of Thurrock Council.

"I understand that an injection of between 100 and 165 million American dollars would ensure the refinery could stay open," he said in a statement. "I have also been told closure of the refinery, even keeping it as a storage facility, would cost the local and national economies more than 100 million pounds."

DECC wasn't immediately available to comment on Thursday's demonstration. A DECC spokeswoman said Monday: "We understand the disappointment workers at Coryton feel, but we are unclear that the demonstrations will do anything to help the situation."

"We do not believe that keeping the refinery open with public money would achieve the aim of securing a sustainable future for the plant," she added.

-Write to Konstantin Rozhnov at konstantin.rozhnov@dowjones.com