There are more of them. They are bigger. And they are more aggressive.

Around the world there have been many stories during the pandemic about a rise in rat sightings.

From New York to London last year there were reports of the rodents migrating.

Experts - not least in pest control - said they thought rats were looking for new sources of food, as shops and restaurants were shut for lockdowns amid the pandemic.

And the very fact more people were working from home meant they were more likely to see the beasts as they moved around.

In Glasgow, the GMB, which represents many cleansing staff, has used a giant inflatable rat - called Cludgie - to represent what it claims is a city waste crisis.

Newspaper reports have said cleansing staff have been “hospitalised” after being “bitten” by rats in “attacks”.

Some workers have been quoted saying there were not only more rats but that they are bigger than usual.

Chris Mitchell of the GMB - who has been the face of his union’s campaign - told The Herald two of his members had been bitten.

“There are more rats because of cuts,” he said.

Local authorities keep detailed reports of rat call-outs to pest control, so what do Glasgow’s official records show?

Well, there have been more sightings of rats outside or in non-living areas since the pandemic.

City authorities had 4399 call-outs for rats in such circumstances in 2019, before Covid, but 5802 in 2020, three-quarters of which included the pandemic.

Call-outs for rats outside and in non-living areas have held up in the first half of this year, when there were 3512. That compares with 3462 in the first six months of 2020, half of which was in lockdown, and 2417 in the same period of 2019, which was pre-pandemic.

In contrast, call-outs for rats in living areas fell slightly, from 1375 in 2019 to 1227 in 2020. The equivalent figure for the first half of this year is 789. Rat call-outs tend to peak in the summer and are low in the winter.

Council officials say no worker has been bitten by a rat and there is no official record of this having happened in recent years.

The Herald has seen health and safety reports for all incidents recorded involving rats. That is a total of six since August 2018, four of them this year.

In five cleansing staff were scratched on their arm when a rodent ran on them after being disturbed in a bin.

Workers were taken to hospital to have their cuts or grazes cleaned and to be given a precautionary tetanus jab.

A sixth incident saw a worker twist his ankle after being startled by a rat. No worker was admitted to hospital - or hospitalised - for further treatment.

Stephen Egan, the official in Glasgow responsible for the cleanliness of parks and streets, said he did not recognise talk of “rat attacks”.

“That is not something I am aware of,” he said. “There have been several unfortunate incidents over the last six to 12 months. Rats are never a good thing. We have had workers who have been scratched and have had to go for a tetanus jag. In the latest situation the guy was back at work in an hour and a half.

“The idea that rats are attacking people on a regular basis is just not evidenced.

“I am not trying to minimise what happened to staff,” he added. “But if you’re working in refuse collection I would have thought that 50 years ago you would come across rats and I would have thought that today you would also come across them to some degree. Because we live in a city of 630,000 people.”

Mr Egan said that overall reports of rat infestations were relatively steady. “The idea that all of a sudden the rat population has exploded is not born out by any stats I see,” he said. However, he said that there was a “plausible scenario” that rats, in search for food, had been moving away from shops towards residential areas during lockdown.

Council officials and the GMB’s Mr Mitchell have been at loggerheads for weeks. The union rep told The Herald all his accounts of rat attacks were truthful.

Mr Mitchell has been collating a rat register, urging the public to come forward with sightings of the pests.

He previously told journalists: “We have had more sightings and attacks with rats more frequently over the last 15 months. Cleansing staff have been hospitalised because of it and say they have never seen so many rats in their whole life.

“The situation is getting worse and worse.”

Council chiefs dismissed the rat register as being “for show”.

Mr Egan said claims there was a crisis in cleansing was affecting a morale and said he was “disappointed” with with criticism from “one particular union”.

“It feels to me like a wee bit of a soundbite,” he said.