Thousands of motorists were caught in 12-mile tailbacks yesterday morning after a rush-hour crash.

The three-car collision happened on the eastbound side of the A27 at Falmer, Brighton.

There were no serious injuries but debris, diesel and oil were strewn across both lanes of the road, which was closed for nearly four hours.

Traffic backed up as far as the Southwick Tunnel on the A27 and the Burgess Hill turn-off on the A23.

Main roads within Brighton were also affected as cars waited to get on to the by-pass and several vehicles broke down after overheating in the queues.

The emergency services were called to the crash at 6.15am. Police said the debris in the road made it unsafe for cars to pass.

Ambulance crews treated three people, thought to be the drivers, for minor injuries and took two to the Royal Sussex County Hospital in Brighton as a precaution.

The vehicles were removed and firefighters washed the road but the Highways Agency said it had to wait for specialist equipment to arrive from Horsham to complete the job. The road was closed until just before 10am.

Caroline Loosen, 28, was more than an hour late for the first day at her new sales job.

She left her home in Turner's Way, Burgess Hill, at 8.30am to get to Hollingbury in Brighton but got trapped in the jam.

The 20-minute journey took an hour-and-a-half and she did not arrive in her office until after 10am. Her husband Chris, who drove her in so she could pick up a company car, was even later getting to his job as a travel consultant in Burgess Hill.

Mrs Loosen said: "I wanted to make a really good impression on my first day and I ended up being late. Thank goodness that my new boss was late as well. He got in even after me."

l More traffic queues are expected from Monday, when work starts on a new bridge to carry the A27 over the railway line at Beddingham, near Lewes.

The £32 million bridge will replace Beddingham level crossing, which has been classified as "high risk" by the Railways Inspectorate.

Traffic should be able to use the bridge towards the end of 2007 and the whole scheme will be completed in summer 2008.