Tidy Northern Ireland is launching a cinema advertising campaign on Thursday to convince the public to clean up its act when it comes to littering the province's streets.

The problem of fast food litter is the most likely cause for a rise in the number of rats in urban areas, with Belfast seeing a marked increase in the problem.

"In ideal conditions within a single calendar year, from two breeding rats you can have up to 1,000 rats just develop from that one breeding pair," explains Roger Fox, branch manager for Rentokil in Northern Ireland.

Traditionally rats have returned to the sewer but in recent times this has not been happening

Jillian Bill Tidy Northern Ireland

Jillian Bill, the campaign manager for Tidy Northern Ireland said unless people realised the error of their ways the problem would get progressively worse.

"How close do you want the rats to get before we ditch our dirty habits and use a bin?" she said.

The advert, to be screened in cinemas throughout the province, shows a couple asleep in bed while rats crawl over the covers.

"Rats are spending more time over ground than under ground and the reason is there is fast food litter being dropped on the streets and they don't have to look too hard to find their next meal," said Ms Bill.

"Traditionally rats have returned to the sewer but in recent times this has not been happening and we are now seeing rats appearing in daylight."

Acute problem

All 26 councils across Northern Ireland are involved in the campaign.

Belfast City Council spends on average �9m per year dealing with the problem of rats, which works out as �26 per citizen.

Martin Doherty, the council's waste manager, said the rats posed a problem.

"Because we don't see them doesn't necessarily mean they are not there," he said.

"Food waste is what gives rise to rats because obviously they need to eat.

"Certain areas of the city would be more acute than elsewhere.

"Places such as outside cinemas and fast food outlets would have a more acute problem with food waste therefore you are more likely to see rats in these areas than you would in other parts of the city."

Mr Fox added: "In the last two to three years we have noticed a marked increase in the amount of callouts and the amount of physical sightings we would have specifically of rats.

"Unfortunately as long as there are people there will always be rats," he added.

"Rats live off the debris we leave behind so as long as we leave debris there will always be rats."