Early loss of leaves, he said, was an "inexorable" sign that mycorisation - the process that produces truffles - had not occurred. Verlhac said that these "truffle trees" had, in many cases, already lost their leaves in the heat and drought. The Tuber melanosporum or "black diamond" of the P?gord, which can sell for €250 (£175) a pound, needs regular downpours in the summer months to develop underground through a symbiotic relationship with the roots of certain trees.M. "The 2003 harvest will be useless and probably the 2004 and 2005 harvests as well," M. Verlhac added.In some areas of the French south, there has been almost no rain since February.

France faces a disastrous truffle harvest this winter - and for the next two winters - because the searing heat this summer has destroyed the breeding grounds of the temperamental and much-prized underground mushrooms. Experts are predicting that few, if any, truffles will be found when the main collecting season begins in December, opening the floodgates to cheap but relatively tasteless truffles imported from China."The prolonged drought has been catastrophic for truffles in all the main truffle producing regions [of France]," said Albert Verlhac, the director of the national truffle research station at Chartrier-Ferri? in the P?gord area of the French south-west. which the relatives need to raise in order to pay the costs of their High Court action.They are planning to sue for compensation four men whom they claim were involved in the attack.Michael Gallagher, whose son Aidan, 21, was among those killed in the Real IRA attack was not part of the delegation in Dublin for the talks with Mr McDowell.But he said: "We have been waiting five years and these arrests have come all of a sudden. A spokesman for the organiser of the arms fair, Spearhead Exhibitions, based in Surrey, said it was "100 per cent" confident that police would ensure the security of the exhibitors and visitors.. A man and woman were being questioned today by detectives investigating the Omagh bomb atrocity. Two groups, Reclaim the Streets and Critical Mass, plan to cause traffic chaos with a mass bicycle ride and protest marches to close off streets.Martin Hogbin, co-ordinator of Campaign Against Arms Trading, said: "Our Government likes to project itself as a force for good in the world, but the reality is that by hosting this arms fair, the UK has become an international force of hypocrisy."Other protest groups include the Anarchist Federation, CND, Reclaim the Streets, Destroy DSEi, Disobedience, Globalise Resistance and Wombles.An MoD spokesman said its involvement in the exhibition was part of its support for the legitimate British arms industry.

There have been calls for direct action and blockades on 10 September, which has been labelled "Destroy DSEi". We have been planning this for a year because of the high level of protest expected, including plans for a day of direct action."Protesters plan a march in central London on 6 September and a demonstration called "Facing the Arms Traders" on 9 September. It is an invitation-only event.The Met said: "It's a big event, very high-profile and seen as controversial, so we expect it to attract a large number of demonstrators. Security fences will enclose the exhibition, which will also be policed by security guards. Plainclothes detectives will also be used to identify known troublemakers, and surveillance teams will monitor the protests. The MoD has invited delegates from 60 countries and will provide them with accommodation and board.The huge security operation, costing more than £1m, includes the deployment of 2,000 frontline police officers from the Met, 300 officers from the British Transport Police, officers from the City of London force and MoD police and specialists from the Met's marine, dogs, and horse units. A frigate and a minesweeper are to be moored outside the centre and a tank and a helicopter will be on show inside.Government ministers are expected to attend the event, which is supported by the Ministry of Defence.

A senior Metropolitan Police officer said they were "expecting serious trouble", and described the planned demonstrations as "a major public order headache".Nearly 1,000 arms companies and suppliers selling artillery, military aircraft, small arms, bombs, mines and tanks will have stands at the Defence Systems Equipment International (DSEi 2003) exhibition at the Excel Centre from 9 to 12 September. Some demonstrators have been told to "dress as smart as you can" to confront arms dealers and government delegates. First built in 1950, it has outlasted the VW Beetle to become the world's oldest production car.. More than 3,000 security guards and police officers will be deployed in London next week to protect Europe's biggest arms fair amid warnings of potentially violent protests.