Every parent wants to protect his or her children from harm and many fear having a mobile phone mast near their homes could potentially expose them to danger.

Although there is still no conclusive evidence masts damage health, a number of families have united to fight mobile giant Vodafone in a desperate bid to stop a 3G mast going up in their community.

Tempers rose at a packed meeting between the phone company and anxious residents on Monday.

Parents fear the mast, which could be stationed just 150m from a primary school, will put their children at risk and are now preparing a legal challenge costing thousands of pounds.

The proposed site, next to a bus shelter opposite the Northlands Wood doctors' surgery in Walnut Park, Haywards Heath, was deemed "controversial" when it was first mooted more than a year and a half ago.

Since then the plan has been rejected twice but campaigners now believe it will be looked upon favourably by the Planning Inspectorate as it goes to a second appeal.

More than 100 people crammed into a suite at the Birch Hotel to confront a representative from Vodafone, many after receiving a letter advertising the meeting just a day before.

Gillian Ashcroft, of Rushwood Close, Haywards Heath, said: "You will be sticking this mast up in the middle of a housing estate full of children, in direct line with the school 150m away.

"Every single study says we will not know for 30 years whether it's safe and personally I'm not happy with my kids being part of an experiment."

Northlands Wood Primary School has already written to Mid Sussex District Council to complain about the plans.

However, after councillors threw out the application, it is now left to Government officers to decide.

Another angry resident shouted: "Property prices are going to plummet because, to be quite honest, I wouldn't buy a house that was right next to a mast."

Vodafone already has two base stations in the Haywards Heath area: One on the water tower at the Princess Royal Hospital and another in Market Place, by the train station.

Speaking on behalf of the mobile phone company, Nicola Whitehead said the phone operators needed the new mast to increase their capacity in the region.

She said: "As much as people don't want the mast outside their houses, they also want to use their phones."

However, residents pointed out that as the mast was to be used solely for the company's 3G service, there was little requirement for it.

People claimed that no one in the area used the third generation mobiles.

One campaigner said simply: "3G is the biggest flop out. Where's the capacity you need to put it in?"

Worried about hazardous affects on their children's health as well as plunging house prices, members of the public packed the room and many had to stand outside.

Stuart Blake, chairman of the Northlands Wood Residents Association, said: "There's a reason why microwaves cook at the frequencies they cook at and they're very similar to the frequencies of mobile phones."

Mrs Ashcroft said: "Until two years ago I was of those people who thought there was no problem with mobile phones but now I've stopped because my ear gets very hot and very sore if I use a mobile for over 15 minutes.

"I even get a scabbed section in my ear if I use the phone for too long.

"I'd like you to tell me that is scientifically normal."

Community relations adviser Ms Whitehead said that all phone services had to meet international standards on radio frequencies (RF) set by the World Health Organisation (WHO).

While some people could be more susceptible to levels of RF than others, these problems would be due to the mobile phones themselves, not the base stations, she added.

Ms Whitehead said: "We are told again and again the level of RF is so low and if they work within these guidelines they are perfectly safe.

"Nothing is going to stop this, in that we need a site, but we still need planning approval."

In an often fraught atmosphere, organiser of the meeting, Councillor Clive Chapman, often had to ask for patience from concerned residents who fired questions at Ms Whitehead.

The loudest cheer was saved for a local insurer who said he believed the masts could not be insured due to the unknown risks they hold.

Possible alternative sites were also put forward by the residents' association, including nearby Pascote's Farm.

However, that site has already been rejected twice as a site for an Orange mast.

The association is now employing a barrister to fight their cause against the company at the appeal hearing expected later this year.

Ms Whitehead promised to re-investigate the farm as well as other sites, adding: "You don't have to trust me but I'm all you've got."

After the meeting, a spokeswoman for Vodafone said the company has full liability insurance.

She said: "We will now go back and revisit all our options.

"We can't give any guarantees but we will look carefully at all the alternatives."

There are now more than 40 million mobile phones in the UK and more than 30,000 base stations.

Vodafone likened the development of 3G technology to that of colour TV from black and white sets.

Research into the safety of both phones and their masts has produced inconclusive results, though some studies have suggested there is a cause for concern.

Most experts agree it is sensible to limit the use of mobiles by young children.

However, there have been no studies into the long-term effects of using handsets, not least because the technology has not been around long enough.

Laboratory tests on mice have shown that radiation from mobile phones can have an adverse effect on their overall health and a study by scientists in Sweden, published in 2002, claimed to have found a link between analogue mobile phones and brain tumours.

However, according to the WHO: "Despite extensive research to date there is no evidence to conclude that exposure to low level electromagnetic fields is harmful to human health."

Campaigners against the Haywards Heath mast have put together a web site at www.northlandswood.co.uk