Managers at Rugby Cement, now part of Cemex, are confident tyre-burning will start again very soon on a permanent basis. The plant has just completed its trials into the controversial method, which protesters claim causes dangerous emissions to be pumped out over the town.

But Mexican owners Cemex, who took over the plant last March, has always denied the claim and said its annual figures showing a record-breaking year in 2005 shows that Rugby Cement is improving its environmental performance - and tyre-burning actually reduce emissions.

It also hopes the results, which put the plant into the ’world class’ bracket, will persuade the Environment Agency to re-start the tyre-burning on a permanent basis.

A spokesperson for Cemex said: "Since taking over RMC in March 2005, Cemex has seen kiln efficiency climb from 70 per cent in 2004 into the ’world class’ bracket at over 90 per cent.

"Last year, this resulted in an increase in production of more than 10 per cent, which is the best ever performance of the works since it came on stream in 2000.

"Rugby is one of the most modern cement plants in the world and has the largest kiln in the UK. Its total capacity - kiln output plus the additives now widely favoured in the construction industry - stands at 1.8Mt of cement."

Cemex also said that a new UK£6.5 million dust filter, which will be installed in the summer, will reduce emissions by a further 40 per cent. It added: "We are also hoping, following recent completion of trials, to secure approval from the Environment Agency for long-term use of chipped tyres as an alternative fuel with a resulting further improvement in emissions."

"Each year 40 million tyres are scrapped in the UK. Using them in cement kilns means that energy is recovered from what would otherwise be considered a waste material. It also reduces our reliance on landfill, minimises illegal dumping, preserves fossil fuels for future generations and helps the industry to control its costs."