Olympics Face Moment of Truth

Organisers of this summer's Olympic Games will try today to halt the embarrassing delays that have beset showpiece projects by finally starting to put a roof over the main stadium.

After falling massively behind schedule, the much-postponed positioning of the 18,000-tonne steel and glass structure - intended as the event's stunning architectural symbol - is due to begin at last.

The arrival tomorrow of inspectors from the International Olympic Committee (IOC) has concentrated the minds of the Greek authorities, who have been criticised for delays, cost overruns and lethargy, tarnishing the build-up to the games' return to their birthplace in Athens for the first time since 1896.

'The first half of the roof will start to move into place within the next few days, probably on Sun day, because the IOC co-ordination commission is coming to start its inspection', said a spokesman for the Athens organising committee.

'It will definitely happen imminently.' The Greeks hope to have the other half of the roof at least moving by Wednesday, to avoid damaging questions at a joint news conference with the IOC.

However, there is growing anxiety that the Olympics could become a target for terrorists. The main venues across the city will not be searched and sealed for another two months, the Greek authorities confirmed yesterday. They have struggled to explain the lax security at the sites that has allowed passers-by to wander freely amid the building work.

'Prior to the games, starting in early July, all the Olympic venues will be searched and secured. Then there will be a lockdown in which they guarded by armed police,' a spokeswoman for the Ministry of Public Order said.

The stadium roof has become a motif for all the problems in Athens. While construction teams managed to build the promised roof over the armadillo-shaped cycling venue, plans to cover the swimming site had to be abandoned when builders could not guarantee the roof would be ready for the start of the Olympics on 13 August.

There have been growing fears that the main stadium roof would have to be scrapped too, and that the 75,000 spectators due to pack inside daily to watch the world's best athletes in action would swelter in temperatures expected to reach up to 30C (100F).

Barring any last-minute hitches, however, hydraulic pistons should at some point today start gliding to put the first half of the giant roof into position. It will take between 30 and 36 hours.

If it does, the Greeks will win no prizes for living up to the first half of the Olympic motto, 'Faster, higher, stronger', but it will reassure a sceptical world that progress is at last being made in Athens.

However, other problems remain. Transport improvements to help cope with the influx of visitors are behind schedule. And the promise to build a new route for the marathon, over its historic route from the site of the battle of Marathon to Athens, may yet be broken. It is still being built.

Builders are now working round the clock everywhere, but officials admit privately that the work took too long to begin.

The Greeks insist the games will be '120 per cent safe', but fresh concern was raised yesterday that the sailing venue could be a terrorist target. John Coates, president of the Australian Olympic Committee and a key IOC figure, said that while security at the rowing and canoeing sites was fine, 'the venue for the sailing is more difficult. It's just a three-star hotel and some apartments, and that's going to be difficult'.

Tony Blair expressed total faith last week in the Greek authorities' ability to keep the games safe, despite three bombs going off at an Athens police station.