SHELL is facing the threat of prosecution by the National Rivers

Authority over the oil slick polluting the River Mersey, it was

disclosed yesterday.

The National Rivers Authority said it had told Shell action was being

considered under the Control of Pollution Act of 1974.

The company has been given 14 days to provide details of the incident

before a final decision is made on possible court moves, said a

spokesman.

Shell's acting manufacturing manager at the Stanlow refinery, Mr Ted

Jenkins, said: ''We are never very comfortable when this sort of thing

happens, as you can imagine.''

The slick of 150 tons of oil, which leaked from a fractured pipeline

carrying crude 12 miles from Tranmere oil terminal, Birkenhead, to

Shell's Stanlow refinery near Ellesmere Port, was yesterday largely

broken up by emergency crews.

However Cheshire County Council's environment chief Mr Derek Bateman

said the company reacted too slowly to the environmental disaster, which

the RSPB warned could be catastrophic for wildlife.

Mr Bateman said: ''It has taken two days for them to assemble the

right people to give the proper advice.''

And he claimed it had taken the oil giant until Sunday night to

release vital equipment to help clean up the 15-mile slick.

''Even if we manage to clear up the river now without further damage

this has put back the river clean-up programme by 20 years overnight,''

he said.

Animal rescue organisations began receiving dozens of oil-coated birds

yesterday.

The RSPB called the spill potentially catastrophic as up to 100,000

wading birds use the Mersey as their winter feeding ground.

RSPB coastal policy officer Mr Philip Rothwell said: ''The Mersey

estuary is part of a network of sites, stretching from Russia and

Northern Canada to Africa, essential to the survival of millions of wild

birds on their migration.

''The implications for bird populations go far beyond our shores and

could last many months, if not years.''

Environment Minister David Hunt held talks with Government officials

and afterwards said he would ensure that Merseyside emergency workers

get ''all the resources and equipment required both at present and as

the clean-up operation continues''.

He said: ''The Department of Energy have informed me that an

investigation into the incident is being carried out by their oil

pipelines inspectorate.''

Environment experts and fire officers from Merseyside and Cheshire

flew over the Mersey by helicopter checking the full extent of the

pollution from Saturday's leak.

Thick, tarry deposits were coating large areas of both banks as far

inland as Warrington and a small army of council workers was busy with a

''bucket and spade'' operation to clear it up.