A PREDICTED gridlock of Britain's road network last week failed to materialise, sparking debate over whether future traffic jams can be anticipated.

Trafficmaster warned that Friday, October 23 would be the worst day yet for delays, with up to 750,000 vehicles held up, caused by darker evenings, the start of school holidays and traditional rush-hour jams. But when the expected log-jam failed to happen, with 650,000 vehicles caught in jams, equalling a record set two years ago, the AA said it showed that most congestion could not be predicted, as often if was caused by unexpected events.

However, Trafficmaster said it showed that keeping drivers informed helped to avoid gridlock and motorists had staggered their journeys, setting off between Thursday and Saturday instead of all on one day, to avoid the jams. Overall, Friday congestion was down by 14% on last year, but reached a much higher peak than normal. Lynn Healey, manager for AA Roadwatch, said: 'The worst gridlock that we have seen in the past couple of years was not to do with the weather, children's holidays or dark nights, but because a lorry got stuck in the Blackwall Tunnel - an event that could not have been predicted.'