Explosives similar to those used to kill more than 200 people in Bali were seized by police today in a major anti-terrorist operation.

Eight men aged 17 to 32 were arrested - three of them in Crawley - during a series of 24 raids in London and the Home Counties.

They are being held on suspicion of being involved in terrorism.

More than half a ton of ammonium nitrate fertiliser, which can be used to make explosives, was found at a self-storage warehouse in west London.

The three Sussex men, all British citizens and thought to be Muslims, are aged 19, 22 and 32.

Addresses in Langley Green and Gossops Green, Crawley, were sealed off as police continued their inquiries.

More than 100 Sussex officers swooped on the homes near Gatwick airport just after 6am in a pre-planned, intelligence-led operation.

Pinakin Patel, who has run the Kandis Sweets shop in Langley Green for nine years, said: "I saw a lot of police cars in the street and in Langley Drive and Juniper Road.

"I was a little surprised but I'm not worried. I am glad the police are taking action."

The raids were led by Scotland Yard with assistance from other forces including Sussex Police.

Dr Abduljalil Sajid, Imam of Brighton, said the Muslim community welcomed and supported any steps to stamp out terrorism. He said: "We were aware of what was going on.

"I have been in contact with senior Metropolitan Police officers and had a meeting with them last week in preparation for this activity. We support our police in arresting all those who are under suspicion of any terrorist action. We do not want evil to remain in our community.

"After Madrid we are all aware anything can happen, anywhere, at any time."

He said as law-abiding citizens, Muslims wanted to see evil nipped in the bud, adding: "We do not want innocent people to suffer."

The imam, who is Brighton and Hove's foremost Muslim leader and director of the city's mosque, said Muslim leaders throughout Sussex had been kept informed about the intended police raids in case of any problems within their communities.

He said: "We are all with the police in terms of bringing peace in our area. We want prevention now rather than cure later. We never wanted Madrid to happen."

Dr Sajid said if those arrested were involved in any terrorist activity they should be dealt with severely. "But if they are found to have done nothing wrong, they must be released after the initial investigation," he added.

Laura Moffatt, MP for Crawley, said she was shocked that arrests had been made in her constituency.

She said: "It is very unsettling news. I have a fantastic population in Crawley from all backgrounds and most of those people, whatever their background, are lovely, peace-loving folk. It is a shock to know some may be involved in terrorism."

Portuguese national Jose Pestana, 41, sparked a major terrorist alert in March last year when crude bombs made from aerosol cans and firework gunpowder were found under a sofa at his flat in Langley Parade.

He was convicted in September of planning to plant two home-made bombs at a restaurant at Gatwick.

The judge at Hove Crown Court said the offence was not terror-related and he was jailed for ten years.

Two of the men arrested today were held in Uxbridge, one in Ilford, one in Horley, one in Slough and three in Crawley.