Travellers found roads clogged, stations closed and aircraft grounded by bomb threats which targeted major transport hubs in the south-east of England.
The warnings, assumed to have been made by the IRA, were timed to cause maximum chaos in the morning rush hour. At one point the Royal Automobile Club described conditions on the roads as "some of the worst for many years, if ever".
At the height of the alert Paddington, King's Cross, St Pancras, Baker Street and Charing Cross mainline and Tube stations were closed and the surrounding roads and buildings evacuated.
According to the RAC, London was a patchwork of areas either packed solid with stranded pedestrians and jammed traffic or cordoned off and eerily silent. Trafalgar Square was empty at one stage after police sealed it off.
On the M25 there was a 10-mile traffic jam and routes into the London from the west were gridlocked. The disruption was at its peak at 9am.
"You have 250,000 vehicles crossing the inner London cordon during the peak rush hour," Martin Mogeridge, a transport consultant, said. "If you targeted, say, four key points particularly in the morning rush hour where drivers have no choice but to carry on into London - then it is relatively easy to bring the roads to a halt."
The first bomb threats - using recognised code words - were received by local shops and hospitals in the centre of London at 6.45am. The earliest targets were the capital's main rail termini.
At 6.49am King's Cross, London's lifeline to the north, was closed. Two minutes later, Charing Cross, serving south London and Kent, was also closed. At 6.53, Paddington was shut down. Surrounding streets were evacuated and buses on routes using central London streets were all diverted.
Air transport was the next to be targeted. Luton, 30 miles north of the capital, was the first of the airports to receive a bomb threat at 6.52am. It was also the last to be back in action, reopening at 3pm with flights resuming more than an hour later. Two suspect packages were found during the search - a wooden box which was exploded by Army bomb disposal experts in a controlled situation, and a package which proved to be harmless.
St Pancras and Baker Street, vital commuter links, were closed at 7am. By then the terrorists had switched targets, focusing on sea-faring passengers. At 7.20am, Kent police received a bomb threat to Dover docks. The harbour area was closed for 40 minutes for a search to be carried out, but again nothing was found.
Gatwick in West Sussex, the country's second busiest airport, was closed at 7.40am. More than 4,000 passengers were stranded in aircraft until the emergency was over and British Airways passenger jets circling the skies above the city had to be diverted to airports as far afield as Southampton, Bournemouth and even to Royal Air Force bases in Kent.
It was more than six hours before both terminals at Gatwick reopened, and then it was with only a patchy schedule. British Airways did not restart flights from the airport until the early evening yesterday. There were also closures at Stansted, in Essex, and Heathrow - where a suspect package was blown up by police at 9am.
The tense atmosphere led to many false alarms. London Underground's Jubilee line was closed for more than 20 minutes, reopening just before 9am after a suspect package on a platform at St John's Wood in north-west London had been checked.
Rail stations outside London did not escape. A coded telephone warning covering the three mainline rail stations in Watford in Hertfordshire, was received at 7am. Watford Junction, a busy commuter stop, was closed at 8.40am. Police carried out a controlled explosion just north of the station, and it was reopened soon after 1pm.
It was afternoon before the capital's rail network resumed, normal services with Paddington the last of the central mainline and Underground stations to reopen at just before noon.Reuse content