Delegates at a national union conference missed vital debates because of huge traffic jams caused by people driving to collect cyclists banned from travelling by rail after a sponsored bike ride, it was revealed today.

Members of Unison complained it took them hours to travel the last few miles into Brighton yesterday because of gridlocked roads.

Around 27,000 cyclists took part in the annual London to Brighton sponsored ride, to raise funds for the British Heart Foundation, but they were banned from travelling on Southern Trains for the day.

The decision to ban all forms of bikes, including folding cycles, led to warnings of travel chaos on the roads and prompted calls for the Government to introduce a cycle-friendly policy for rail operators to abide by.

One Unison delegate said today: "I missed vital debates at the conference because I was stuck in traffic for over two and a half hours. It was so frustrating.

"I wasn't able to represent my members. I don't understand how a rail company can ban bikes on one of the busiest days of the years for bike travel - it just seems barmy.

"We are being told all the time to go green, but the roads were clogged with cars and vans meeting the cyclists."