The bottles were collected and recycled

If the bottles had been laid end to end, there would have been enough to circle the circumference of the Millennium Stadium 10 times.

Workers from Cardiff council collected 800kg in plastic water bottles as a result of the event.

Cardiff council said that was part of efforts to hit recycling targets.

More than 4,000 people took part in the marathon on 3 October.

Thousands of runners took part in the marathon

Staff from the council's Waste Management Service manned the route to collect the water bottles discarded by the runners.

The bottles were then taken to a processing facility where they were put into bails and distributed to contractors for reprocessing.

" I am delighted to hear that the marathon recycling initiative was a total success," said Phil Sherratt, chief officer of waste management.

"Cardiff is developing a challenging waste strategy that has been devised to exceed the recycling targets set by the Welsh assembly.

"As well as the kerbside collections and other recycling initiatives, we are keen to provide recycling facilities for future events across the city," he added.

It is estimated that 80% of post-consumer plastic is buried in landfill sites in the UK, with 8% is incinerated in energy from waste plants and just 7% recycled.

In 2003, 350 tonnes of plastic was recycled in Cardiff.