People caught up in the chaos of London's terror blasts spoke of their relief as they returned to Sussex last night.

With the death toll confirmed at 37 and news that more than 700 had been injured, they remained defiant in the face of the terrorist attacks which rocked the Underground and wrecked a bus.

Brighton Pavilion MP David Lepper's son Joe Lepper, 33, a journalist from Brighton, said: "There was a real sense of calm in London, I think because of the history of the IRA and knowledge of previous terrorist attacks around the world. There was a sense of getting on with it."

Daniel Barrow, 39, from Preston Park, Brighton, said: "It's surprisingly calm but there is a definite strange atmosphere. It reminded me of what the Blitz would have been like. There was a seriousness and a determination to get on with things. Even at the station it was completely calm and not crowded. I even got a seat on the train coming back. There were buses running but a lot of people seemed to be avoiding them and going on foot."

Liz Slimon, 29, a team assistant, of Clarendon Road, Hove, said: "It has been very scary. Everybody was pretty shaken and shocked. I got into work just after it had happened and everyone had heard this loud bang. At first they thought it was thunder.

"One of my colleagues was about to get on the bus that blew up. The driver shut the doors because it was too crowded and it drove off.

Then he saw it explode in front of him further down the street.

"Out of the 500 people in my office, only two or three have been directly affected which is quite lucky. If it had been an hour earlier I think it would have been a lot worse."

Civil servant Claire Wigans, 41, from Brighton, who works near Westminster, said she planned to go to work as normal today. She said: "There was one woman at work who was in the first carriage of the Tube that got bombed. She is still in hospital.

"It could have been a lot worse and we thought of 9/11 when we heard the planes and helicopters flying overhead. Considering what happened in America it was not as bad as it could have been."

The first explosion ripped apart a train between Aldgate East and Liverpool Street stations just before 9am.

Minutes later, a second tore through a Picadilly Line train into Kings Cross and another destroyed a train into Edgware Road Tube station.

The roof of a bus, packed with people evacuated from the Underground, was ripped off in Tavistock Square in the fourth blast.

Sue Jacobson, 54, from Saltdean, who works for Westminster City Council in the transport department, said: "It was really quite frightening because nobody knew what was going on. I travel with a commuter group and we were all texting each other contradictory information.

"Some people were saying they had been told to go home early, some had been told to go late. We just didn't know. The buses were dead and there were no Tubes."

Victoria Brinkley, 36, from central Brighton, said: "One of our colleagues knew someone on one of the Tubes. Others saw people coming out of the station covered in blood."

Adrienne Harman, 56, of Tangmere, Chichester, said: "When I left work, a lot of people were walking and not taking public transport. I heard a man on his phone saying he had seen things that would stay with him forever."

Financial adviser Chris Jane, 26, from Haywards Heath, said: "I came into work early and heard loud bangs just round the corner. There have been sirens everywhere all day."

Sussex Police drafted in reinforcements across the county to step up security and provide reassurance. Extra police were on duty at Gatwick airport and at other key transport locations, urging people not to travel to London today. Operation Padlock was designed to increase police visibility and decrease fear.

Police said there were no incidents in Sussex but there were two scares.

Vandals attacked a mobile phone mast at Truleigh Hill, Shoreham, early yesterday.

There were fears it was connected to the bombings but this was quickly ruled out by police. They said the damage had caused little disruption to communications.

Brighton station was also shut for several hours when an abandoned briefcase sparked a bomb scare and had to be blown up.

Surrounding roads were closed and train services were halted before the all-clear was given.

Following claims from an Al Qaida-linked group that it was responsible for the London attacks, Brighton and Hove Muslim Forum (BHMF) released a statement condemning the attack.

It said: "The BHMF urges calm. Mosques and centres across Brighton and Hove have been contacted by Brighton police."

A police spokeswoman said: "This is just a precaution should someone decide to take matters into their own hands.

"We have advised groups that a special serial number has been assigned on our computer that will record any incidents of threatening behaviour or anything of that nature.

"We do not anticipate problems and we believe everyone will remain calm and act sensibly."

St John's Church, in Knoyle Road, Brighton, was also open last night for quiet prayer.

Sussex ambulance crews and experts from Queen Victoria Hospital's burns unit in East Grinstead were sent to London to help.

Fire services in Sussex were on standby all day yesterday in case crews were needed in London.

As the Queen announced Buckingham Palace would fly the Union Jack at half mast as a mark of respect after yesterday's events, councils across Sussex said they would guided by national feeling.

Brighton and Hove City Council met twice yesterday to establish what action should be taken in the city.

Security has been stepped up at council buildings until further notice and trained social workers were sent to Brighton station to talk to distressed commuters as they returned home.

The council warned schools parents might not be able to pick children up on time because of delays to transport and asked the them to make sure children were looked after.

A spokesman said a decision on whether to fly the flag at half mast would be made today and the council would take part in any national memorial services that are planned.

Both Chichester Borough Council and Worthing Borough Councils said they would be guided by national feeling on whether to fly flags at half-mast.

A spokeswoman for Eastbourne Borough Council said flags on all council buildings across the town would fly at half mast.

Michael Foster, Labour MP for Hastings and Rye, was on a train to London when the attacks happened.

The train stopped at Battle and Sevenoaks where passengers were told to make their way home.

He said: "I have spoken to a number of people who were there when it happened but so far everyone seems to be okay. There is a state of almost stillness about everything.

"It is going to be a worrying time but we cannot allow this atrocity to weaken our resolve to conquer terrorism and to carry on in as normal a way as possible."

Nicholas Soames, MP for Mid Sussex was in London all day yesterday.

He called the attack wicked and cowardly.

He said: "This has been an appalling event conducted by ruthless terrorists with the aim of inflicting the maximum damage possible.

"I am amazed by the way the emergency services and doctors and nurses have coped. They have all been astonishing."

Lewes MP Norman Baker last night walked from his Westminster office to Victoria Station to see if trains were running to Sussex.

He said: "The feeling in the Commons was rather subdued but determined.

"My researcher was on a bus on the same route about five minutes ahead of the one which exploded so he was rather shaken when he arrived."

Meanwhile police officers were at main railway stations across Sussex during the late afternoon and evening to talk to anyone needing help and assistance.

Worried relatives seeking information about loved ones should call the police hotline on 0870 1566 344.

IT worker Sam McGregor, 37, from Hove, said: "I wanted to get home early so I left at 12.30pm but there was no way I was going anywhere because Victoria was closed.

"Everyone in London seemed really quite calm.

"There were lots of police rushing around and sirens but it all seemed to be really well organised."

Ron Biswell, 45, of Queen's Park, Brighton, said: "There was a lot of misinformation in the morning.

"At first they were saying there were power failures and no one knew what was going on.

"I wasn't worried about coming back on the train because I thought it was all over.

"It would be a bit cynical of the bombers to get people on the way home."

Stephen Osborne, 35, from Brighton, said: "I work near Aldgate so it was quite worrying hearing all the sirens. Everyone in the office knew someone who was affected."