The petrol protesters' stranglehold on UK fuel supplies began to ease today as the first tankers of fuel left the depots.

The Government used emergency powers to order oil companies to deliver petrol to hundreds of priority stations across Britain Tankers left Purfleet at 7.30pm, others left Grangemouth in Scotland, Hamble near Southampton, Stanlow, in Cheshire, and Manchester.

A DTI spokesman said: "There are specified sites that we have asked oil companies to prioritise and those sites are evenly spread across the country."

But in Shoreham today, no petrol moved as protesters continued their blockade.

Despite Prime Minister Tony Blair's assurances that police would escort tankers, they took no action at Shoreham Harbour this morning.

Inspector Richard Newman, of Hove police, said they had not been asked to escort any vehicle.

He said: "Sussex Police continues to monitor the current situation both locally and nationally. We have not currently been asked to escort any vehicle.

"We acknowledge the right of people to protest peacefully and we continue to liaise and monitor the situation.

"If drivers choose not to cross the picket lines it is a matter for their companies and not the police."

But there was confusion surrounding the crisis today and this led to a second demonstration.

Tanker drivers, who said they wanted to pick up and deliver fuel, used their vehicles instead to block one entrance to the depot. They said they were not being allowed through and they would continue their demonstration until they were.

One of the drivers, Steve Hanson, from Uckfield, said the Shoreham Port Authority should ask the police to allow them through.

He said he agreed with the fuel tax protest but jobs were now at stake and it was time to get back to work.

Protesters, however, said they were resolute and were not moving.

A Worthing taxi driver, who would only give his name as Ian, said he has a pregnant wife and a mortgage and his 11-year old business was in jeopardy because of the high cost of petrol.

He said: "Most people in this country agree with us."

Henfield farmer Shaun Hazelben, said: "We have a good cause and we are not being violent.

"I don't mind paying taxes but I just want them to be fair - 75p in the pound for fuel is too high and hurts everything in this country."

The protesters were using Range Rovers, vans and private cars to line the road into the depot, making it impossible for tankers to get through.

Another farmer, from Horsham, said: "We all have businesses to run and they are all going down the Swanee. I've never been on a picket line before but this fuel tax is disgusting and has made me take action."

The demonstrators said if police did physically move them from the scene they would continue the protest by other means, possibly by organising go-slows in main roads in Sussex.

Tony Blair spent yesterday in emergency talks with senior police officers and oil industry bosses.

Health authorities had warned the fuel shortages were putting patients' lives at risk.

Panic buying spread from fuel to food as consumers fearing the worst stocked up on essentials and the Royal Mail warned it only had supplies for one more day of deliveries in some areas.

The Prime Minister predicted things would start getting back to normal by tonight and insisted he could not "responsibly" introduce an emergency budget to alter taxes on fuel.

He told firms it was up to them to ensure supplies reached the public after police chiefs said the protests should not prevent tankers leaving to fill up the forecourts.

Police had agreed to do "all that is necessary" to protect drivers.

He said: "Everything is now in place to get the tankers moving."

But experts predicted another week of misery for Sussex motorists as oil companies struggle to fill petrol pumps.

The AA reported the county's roads as "dead" this morning while thousands of desperate employees took the train to work.

Banks, supermarkets and the emergency services say mayhem could ensue if the fuel crisis does not abate.

The Petrol Retailers' Association warned today of up to three weeks' continued disruption.

As tankers started to roll, spokesman Ray Holloway said: "In no way is one day going to make any difference. It will take three weeks for us to get back to where we were before this crisis began."

It would be Saturday at the earliest before supplies were generally available to the public anywhere, he warned.

Refuelling could take anything up to three weeks.

The roads of Sussex were emptier than usual this morning.

AA spokesman Rebecca Rees said: "Petrol is only getting through to a limited number of stations. It's going to take ages.

"For Tony Blair to say that things will be relatively normal again within 24 hours is rather hopeful. It's going to last another five to six days for things to start getting back to normal.

"Only a few tankers are leaving a few refineries, probably less than one per cent.

"People should only make essential car journeys, fill up where possible and maximise fuel efficiency."